- not strong; liable to yield, break, or collapse under pressure or strain; fragile; frail: a weak fortress; a weak spot in armor.
- lacking in bodily strength or healthy vigor, as from age or sickness; feeble; infirm: a weak old man; weak eyes.
- not having much political strength, governing power, or authority: a weak nation; a weak ruler.
- lacking in force, potency, or efficacy; impotent, ineffectual, or inadequate: weak sunlight; a weak wind.
- lacking in rhetorical or creative force or effectiveness: a weak reply to the charges; one of the author's weakest novels.
- lacking in logical or legal force or soundness: a weak argument.
- deficient in mental power, intelligence, or judgment: a weak mind.
- not having much moral strength or firmness, resolution, or force of character: to prove weak under temptation; weak compliance.
- deficient in amount, volume, loudness, intensity, etc.; faint; slight: a weak current of electricity; a weak pulse.
- deficient, lacking, or poor in something specified: a hand weak in trumps; I'm weak in spelling.
- deficient in the essential or usual properties or ingredients: weak tea.
- unstressed, as a syllable, vowel, or word.
- (of Germanic verbs) inflected with suffixes, without inherited change of the root vowel, as English work, worked, or having a preterit ending in a dental, as English bring, brought.
- (of Germanic nouns and adjectives) inflected with endings originally appropriate to stems terminating in -n, as the adjective alte in German der alte Mann (“the old man”).
- (of wheat or flour) having a low gluten content or having a poor quality of gluten.
- thin; not dense.
- characterized by a decline in prices: The market was weak in the morning but rallied in the afternoon.
- lacking in physical or mental strength or force; frail or feeble
- liable to yield, break, or give way
- lacking in resolution or firmness of character
- lacking strength, power, or intensity
- lacking strength in a particular part
- not functioning as well as normal
- easily upset
- lacking in conviction, persuasiveness, etc
- lacking in political or strategic strength
- lacking the usual, full, or desirable strength of flavour
- grammar
- denoting or belonging to a class of verbs, in certain languages including the Germanic languages, whose conjugation relies on inflectional endings rather than internal vowel gradation, as look, looks, looking, looked
- belonging to any part-of-speech class, in any of various languages, whose inflections follow the more regular of two possible patterns
- (of a syllable) not accented or stressed
- (of a fuel-air mixture) containing a relatively low proportion of fuel
- having low density or contrast; thin
- (of an industry, market, currency, securities, etc) falling in price or characterized by falling prices
