Etymology * The noun is from Middle English infirme, from Latin infirmus (“weak, feeble”). * The verb is from Latin īnfirmāre, from īnfirmus (“sick, weak, infirm”) + -ō.
1
Weak or ill, not in good health.
He was infirm of body but still keen of mind, and though it looked like he couldn't walk across the room, he crushed me in debate.
[…] Here I stand your slave, A poor, infirm, weak, and despis’d old man.c. 1603–1606, William Shakespeare, “The Tragedie of King Lear”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act III, scene ii]:
1 more example
There will be special drop-off points at all polling stations for vehicles conveying voters who are sick, infirm, or disabled.2023 August 30, “Security Advisory For Polling Day”, in Singapore Police Force, archived from the original on 31 Aug 2023:
2
Irresolute; weak of mind or will.
Infirm of purpose! Give me the daggers: […]c. 1606 (date written), William Shakespeare, “The Tragedie of Macbeth”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act II, scene ii]:
[…] vehement passion does not always indicate an infirm judgment.1797, Edmund Burke, “Letter III.”, in A Third Letter to a Member of the Present Parliament, on the Proposals for Peace with the Regicide Directory of France, London: […] F[rancis] and C[harles] Rivington, […]; sold also by J[ohn] Hatchard, […], →OCLC, page 30:
3
Frail; unstable; insecure.
He who fixes upon false Principles, treads upon Infirm ground, and so sinks […]1692–1717, Robert South, “The Practice of Religion Enforced by Reason”, in Twelve Sermons Preached upon Several Occasions, volume (please specify |volume=I to VI), London, page 3:
Etymology * The noun is from Middle English infirme, from Latin infirmus (“weak, feeble”). * The verb is from Latin īnfirmāre, from īnfirmus (“sick, weak, infirm”) + -ō.
1
To contradict, to provide proof that something is not.
The thought is that you see an episode of observation, experiment, or reasoning as confirming or infirming a hypothesis depending on whether the probability of it being correct increases or decreases during the episode.