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