I have been searching for a word, which I'm beginning to doubt exists at all, that describes a person or thing that changes from one state to the opposite of that state frequently, i.e. an adjective describing the binary oscillation of some particular state.

Words like mercurial or capricious are similar but they only indicate that something changes in general, not necessarily to its opposite. I'm looking for something that indicates an antipodal change.

The closest word I have found is bipolar but, as this refers primarily to a mental disorder, I feel its application to things like the weather or someone's cooking is too poetic. I want a word that is more literal.

Oddly, and with great frustration, I find that while the definition of bipolar is something like "having or relating to two poles or extremities", which specifically implies opposition, all of the synonyms I find for "bipolar" are only describing a general tendency to change.

_____________ - a person or thing that frequently switches between opposite states or dispositions

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    Critias applied the term “buskin” (kothornos) to Theramenes by way of accusing him of switching back and forth between democratic and oligarchic principles, since the sort of boot associated with both tragedy and soldiering fit left or right foot indifferently. See Xenophon Hellenica 2.3 §§30–31 & 47. Commented Jun 27, 2015 at 22:33
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    I would use a two-word phrase: "X fluctuates wildly," since "opposite states" doesn't appear to be intended in a particularly precise and rigorous way.
    – Sven Yargs
    Commented Jun 28, 2015 at 8:40
  • If being used negatively, e.g. when someone is annoying you by never sticking to the same idea, "incoherent" is a possibility.
    – Arc676
    Commented Jun 28, 2015 at 12:30

11 Answers 11


Bipolar seems to best suggest switching between extremes along the same line or element, the association with mental illness is a consequence of the word bipolar being a good fit because depression and mania are considered polar to each other, like north and south poles in the axis of the earth, etc. Common usage like applying it to mental health does not eliminate the function of the base word, no more than than the issue of being gay has taken on additional meaning over time.

  • Thanks for your contribution, both to the debate and to the site. Where possible a citation or example should be added to your answer. This is simply to stop discussion turning into Shall /Shan't & 'Tis /'Tisn't. Hope to hear from you again.
    – Hugh
    Commented Jun 28, 2015 at 21:37
  • Bipolar expresses only the binary nature, not switching between the two poles. Bipolar in psychology involves switching between poles, but the question is not about psychology. In general, bipolar just means having two poles.
    – Drew
    Commented Jun 28, 2015 at 23:24
  • I really didn't want this to be the best word (bipolar) but after reading all the responses and letting the issue sit on a back burner for a while I think this really is the most appropriate word.
    – Jason
    Commented Jul 14, 2015 at 12:30

A vacillator, perhaps?

Vacillate: Waver between different opinions or actions

They view him as a vacillator whose tactical shifts in the face of foreign pressure have been unpardonable. (Oxford)

Unlike mercurial or capricious, vacillator has a back-and-forth implication. Maybe not exactly opposite ends, but it does imply that the vacillator tends to switch their opinion, rather than simply change it to anything.


A flip-flopper

a person who continually changes a point of view or decision, esp. a politician (Dictionary.com)


(verb) to make a sudden or unexpected reversal, as of direction, belief, attitude, or policy (Dictionary.com)
(noun) a sudden or unexpected reversal, as of direction, belief, attitude, or policy



  • a person or thing that oscillates


  • To waver, as between conflicting opinions or courses of action; vacillate:

    • "The court has oscillated over the decades from more liberal to less, more conservative to less, depending upon who was president at the time of vacancies"

The Free Dictionary


Vacillating, as already suggested, is probably closest to what you're looking for, but for different shades of meaning you could try fickle, which is defined by the AHD as "changeable in affections," or inconstant, which can mean about the same thing.


Another option might be ambivalent:
Defined in Wicktionary as:

  1. Simultaneously experiencing or expressing opposing or contradictory feelings, beliefs, or motivations.
  2. Alternately having one opinion or feeling, and then the opposite.

This may or may not be appropriate for your particular use since definition 1 refers to having mixed feelings simultaneously while def. 2 does have your desired meaning.
I think that most people who seem to vacillate between two opposite opinions are often ambivalent deep-down and it is really only their expressed opinion which actually vacillates.

  • A good word but I don't feel it captures the binary aspect with enough exclusivity. If I wrote something like "the weather here is ambivalent" it would sound like a personification, like the weather has opinions. If I said "the weather is bipolar", however, it does not imply any sentience, only a changing between two extremes.
    – Jason
    Commented Jun 28, 2015 at 19:51
  • @Jason- yes, Ambivalent certainly doesn't work with things like the weather- it's for people/things that can think and have opinions. I don't think I'd use bipolar to describe the weather either. Weather is variable and ranges from one extreme to the other
    – Jim
    Commented Jun 28, 2015 at 19:58

It's not Standard English, but in electrical engineering, a circuit that is continuously switching between opposite states is said to be astable. It would make sense to me to apply it to a person or thing as well.


How about the word (constantly) alternating (used as an adjective)?

Example (though with the verb to alternate):

She often alternates between depression and joy.

The words fluctuating, vacillating, oscillating, flip-flopping and (constantly) [wavering between X and Y] (as well as their respective nouns and verbs) are also good candidates, as already suggested by others. However, it all boils down to the context in which you want to use the word. Still, the above are good general answers.


Volatile - Doesn't capture the binary nature, but captures the frequent switching.

(Vacillating, proposed by @jsoteeln, is probably the best choice, IMO.)


Paradoxical is a possible alternative.

Paradoxical adj.

Contradictory in nature

Paradox n.

A person, thing, or situation that exhibits inexplicable or contradictory aspects: "The silence of midnight, to speak truly, though apparently a paradox, rung in my ears" (Mary Shelley).

Source: http://www.thefreedictionary.com/paradoxical


Juxtapose? Strictly speaking you're placing side by side for comparison but if you juxtapose an argument you're effectively switching sides.

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