Definition of "Weak" :

adjective: deficient in intelligence or mental power

"A weak mind."

adjective: overly diluted; thin and insipid

"Weak tea."

adjective: likely to fail under stress or pressure

"The weak link in the chain."

adjective: wanting in moral strength, courage, or will; having the attributes of man as opposed to e.g. divine beings

adjective: deficient in magnitude; barely perceptible; lacking clarity or brightness or loudness etc

"Weak colors."

adjective: not having authority, political strength, or governing power

"A weak president."

adjective: (used of verbs) having standard (or regular) inflection

adjective: lacking bodily or muscular strength or vitality

adjective: deficient or lacking in some skill

"He's weak in spelling."

adjective: (used of vowels or syllables) pronounced with little or no stress

"A weak stress on the second syllable."

adjective: wanting in physical strength

"A weak pillar."

adjective: tending downward in price

"A weak market for oil stocks."