Infirm Definition

ĭn-fûrm

adjective

infirmer, infirmest

Not firm or strong physically; weak; feeble, as from old age.

Webster's New World

Not stable, firm, or sound; frail; shaky, as a structure.

Webster's New World

Not firm in mind or purpose; not resolute; vacillating.

Webster's New World

Not secure or valid.

An infirm title to property.

Webster's New World

Fail; unstable; insecure.

Wiktionary

Synonyms:

Antonyms:

verb

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 your probability for it increases or decreases during the episode.

Wiktionary

Other Word Forms of Infirm

Adjective

Base Form:

infirm

Comparative:

infirmer

Superlative:

infirmest

Origin of Infirm

Middle English infirme from Old French from Latin īnfirmus in- not in–¹ firmus strong, firm dher- in Indo-European roots

From American Heritage Dictionary of the English Language, 5th Edition
Borrowing from Latin infirmus.

From Wiktionary