I've checked Oxford Advanced Learners for acute:

an acute illness is one that has quickly become severe and dangerous

And for chronic:

lasting for a long time

Can a disease be both "acute" and "chronic" simultaneously? For example it could be the case where a certain illness quickly becomes serious and have long term consequences
Are there any "obtuse illnesses" ?

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    I just realized why you mentioned "obtuse"...Obtuse is the "opposite" of acute in geometry, but not medicine. – JeffSahol Sep 9 '13 at 19:11
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    -1 The definitions you've quoted indicate the difference. Acute "quickly become[s] severe and dangerous" e.g. requiring hospitalisation, but when dealt with properly, then comes to an end. Chronic "last[s] for a long time", probably for the rest of one's lifetime, but may come on slowly and is not permanently "severe and dangerous" - but there may be acute episodes from time to time. – TrevorD Sep 9 '13 at 23:08

A chronic condition is one that persists for a long time. Asthma is a chronic condition: if you have asthma today, then you almost certainly had asthma yesterday and will still have it next week. Source and more details: Medline, OED.

Acute has two relevant meanings. In colloquial usage, it just means severe; so in that sense, a condition can be both acute and chronic. However, in medical language, it is specifically used in contrast to chronic; an acute condition, in this sense, is something which by its nature is (expected to be) of limited duration; something which develops over a short timescale. So in this technical sense, a condition cannot be both acute and chronic. An asthma attack is acute in this sense: it’s a temporary flare-up of the underlying chronic condition. Source and more details: Medline, OED.

Obtuse is essentially irrelevant to these medical usages; it was used in a comparable sense in the past, but this usage is now extremely rare (OED; Google ngrams). In mathematics, however, it is still used in contrast to acute. An acute angle is one measuring less than 90°, while an angle more than 90° (but less than 180°) is obtuse.

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  • Your answer would be better if you cited sources for your definitions. And the word obtuse does have a medical usage, meaning "dull, not acute," such as an obtuse pain – JLG Sep 9 '13 at 23:34
  • @JLG: Fair point; will add sources for the definitions. The corresponding use of obtuse, though, is I think obsolete or almost so: the OED marks it as such, and the Google ngrams graph for obtuse pain seems to corroborate this. – PLL Sep 10 '13 at 3:18
  • Thank you. Maybe try to use sources that don't require a subscription (like the link to the OED). It will not help users who do not have a subscription. – JLG Sep 10 '13 at 13:42
  • @JLG: I realise that; that’s why I linked other sources as well. It is a shame that the OED is paywalled, but for many things it’s the most authoritative and detailed online source I know, so I usually try to include both it and something more accessible. – PLL Sep 10 '13 at 16:27



Acute conditions are severe and sudden in onset. This could describe anything from a broken bone to an asthma attack. A chronic condition, by contrast is a long-developing syndrome, such as osteoporosis or asthma. Note that osteoporosis, a chronic condition, may cause a broken bone, an acute condition. An acute asthma attack occurs in the midst of the chronic disease of asthma. Acute conditions, such as a first asthma attack, may lead to a chronic syndrome if untreated.

Obtuse is a geometry term. Being called obtuse is generally considered an insult.

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  • So "acute" may cause "chronic" and vice versa? But I think "chronic " causes "acute" doesn't make sense; since the attack should be accounted as a result of "chronic" otherwise what is the point in coining this term as a disease property ? – Zeta.Investigator Sep 9 '13 at 19:15
  • @Zeta The quotation comes from a medical website. What qualifications do you have to say that their description & classification "doesn't make sense"? – TrevorD Sep 9 '13 at 22:50
  • @Zeta To explain further, as mikeY says, if you've got osteoporosis, that is an underlying chronic condition; because of it you may get a broken bone, which is a short term acute condition. The broken bone will heal, but the underlying chronic condition continues. Likewise, you may have an underlying disease of asthma - a chronic condition; as part of that, you may, from time to time, get individual serious acute asthma attacks, needing hospital treatment. Again, the individual acute attacks will pass, but you still have the underlying chronic condition. – TrevorD Sep 9 '13 at 22:52

The link, you cited, mentions that in case of illnesses, acute and chronic are antonyms.

The adjective Obtuse, which means slow or unwilling to understand something, is not used with illnesses.

P.S.- Acute angle and Obtuse angle are nouns, which are used in geometry.

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  • Actually I looked up the definitions from the 6th version – Zeta.Investigator Sep 9 '13 at 19:26
  • @Zeta "6th version" of what? – TrevorD Sep 9 '13 at 22:37
  • @TrevorD What could it be? Oxford Advanced Learners Dictionary. Did you even read the post? – Zeta.Investigator Sep 10 '13 at 6:23
  • @Zeta As will be apparent from my other comments (which you appear to have ignored), I did read the post and your quoted definitions - and understood them, and have attempted to explain them to you. – TrevorD Sep 10 '13 at 10:18

A chronic disease can have an acute onset or acute symptoms, but the disease itself would not be considered acute.

There is no such thing as an "obtuse illness"

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