If I'm not healthy, am I sick or am I ill?

Are these interchangeable, or do they merely overlap?

  • 1
    There might be some old, technical difference, but, nowadays, they're used synonymously, at least where I grew up. It'll be interesting if a distinction still exists anywhere...
    – kitukwfyer
    Mar 19, 2011 at 23:43
  • 1
    Necessary reference for the modern usage of sick ;-)
    – Sebastian
    Jun 10, 2011 at 12:35
  • 1
    Here's a simple and logic explanation. The origin of sick is from the old Germanic verb: siech which means to have a disease. It was used in Middle High German and refers to people who had leprosy. These people were sent to a: Siechenhaus the resemblance of which can still be found today in the Dutch word for hospital: ziekenhuis....so actually sick would then mean siech = have a disease....whereas hospital simply means a house for strangers. Similar words are: host, hospitable, hostel, hotel and many more...here we have the Latin origin in contrast to the word sick which has Germanic roots.
    – user69223
    Mar 18, 2014 at 8:24
  • Very, very few pairs of words are totally interchangeable. Aug 12, 2016 at 19:29

3 Answers 3


They're generally used synonymously these days, though there was originally a distinction in meaning. "Ill" generically referred to being unwell, whereas "sick" referred to vomiting — this still persists to some degree.

In modern times there has been (and still is to a degree) a distinction between upper-class and non-upper-class usage in British English. See the Wikipedia article for example. The upper-class usage, unsurprisingly, seems to preserve the more traditional meanings of the two words.

U                         Non-U
Ill (in bed)              Sick (in bed)  
I was sick on the boat.   I was ill on the boat.  

Finally, if you're curious you can take a look at the etymologies of sick and ill. The latter originally only meant "morally evil", curiously enough. This is going back to the high Middle Ages, however. Meanings have been are still in constant flux.

  • 2
    Yes, that also explains usages like ill-formed or ill-advised.
    – Tomalak
    Mar 20, 2011 at 1:37
  • @Tomalak: Indeed, those terms inherit from the older definition.
    – Noldorin
    Mar 20, 2011 at 2:15
  • 1
    Surprisingly, ill is not etymologically related to evil, according to the Oxford English Dictionary, though they have been synonymous from the 12th century. Mar 20, 2011 at 12:14
  • @Cerberus: I wasn't implying they were etymologically related, but they have meant the same thing for a long time. I know of no earlier meaning of the word. (If there is one, it's pretty irrelevant anyway.)
    – Noldorin
    Mar 20, 2011 at 19:08
  • 1
    @Noldorin Your assertion that the two are synonymous is only correct for North American English: Brits use sick as a synonym for "vomit", both the noun and the verb.
    – msanford
    Apr 19, 2011 at 4:03

Normally you feel sick when you are ill.

And to be sick often is a synonym to throwing up.

Update: Both words can mean great or wild in recent (hip-hop) slang.

That DJ has some sick skills

  • It's not just hip-hop slang; that meaning of the word has entered wider American youth culture, and even extended internationally.
    – Noldorin
    Mar 20, 2011 at 19:09
  • Hence the (hip-hop) in brackets
    – mplungjan
    Mar 20, 2011 at 20:25
  • 2
    I'm not sure it's any more "normal" to feel sick when you're ill than it is to feel ill when you're sick. Jun 1, 2013 at 23:18
  • To add to FFs comment, if "sick" means "feeling like I am going to throw up" I do not always feel sick when I am ill.
    – skymningen
    Jan 23, 2015 at 14:01

Be aware that sick has lately taken on some new freight: in current slang usages it is replacing awesome as the clichéd announcement of approval.

That is just sick!


That is so sick!

are not used to mean unwell or ill. And while you may not have any trouble distinguishing the meanings when applied via the demonstrative pronoun that, the word is also being applied to personal pronouns as well:

He's so sick!

can mean the speaker is commenting about some outstanding qualities the subject has. Really.

  • This is true, but most likely not what the questioner is getting at...
    – Noldorin
    Mar 20, 2011 at 2:16
  • ...As a teenager, I think that this is pretty old. I mostly just read "sick" used like that in old YA books from the nineties/ early 2000's...Could be regional, though. It seems like slang varies more than anything else does regionally.
    – kitukwfyer
    Mar 20, 2011 at 3:09
  • 1
    @Noldorin: No, it's not what he's getting at, but it is germane to the discussion.
    – Robusto
    Mar 20, 2011 at 3:11
  • @kitukwfyer: I hear it all the time in video gaming and at the poker tables.
    – Robusto
    Mar 20, 2011 at 3:12
  • I wonder how the other guys missed this particular connotation of the word
    – n0nChun
    Mar 20, 2011 at 4:26

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