adjective \ ˈwēk \
|Updated on: 15 Jul 2018

Definition of weak

1 : lacking strength: such as
a : deficient in physical vigor : feeble, debilitated
b : not able to sustain or exert much weight, pressure, or strain
c : not able to resist external force or withstand attack
d : easily upset or nauseated
  • a weak stomach
2 a : mentally or intellectually deficient
b : not firmly decided : vacillating
c : resulting from or indicating lack of judgment or discernment
d : not able to withstand temptation or persuasion
  • the spirit is willing but the flesh is weak
3 : not factually grounded or logically presented
  • a weak argument
4 a : not able to function properly
  • weak eyes
b (1) : lacking skill or proficiency
  • tutoring for weaker students
(2) : indicative of a lack of skill or aptitude
  • history was my weakest subject
c : wanting in vigor of expression or effect
  • a weak translation of the poem
5 a : deficient in the usual or required ingredients : dilute
  • weak coffee
b : lacking normal intensity or potency
  • a weak radio signal
  • a weak strain of virus
6 a : not having or exerting authority or political power
  • weak government
7 a : of, relating to, or constituting a verb or verb conjugation that in English forms the past tense and past participle by adding the suffix -ed or -d or -t
b of a noun or adjective declension in Germanic languages : retaining a lesser number of distinctions in case, number and gender
8 a : bearing the minimal degree of stress occurring in the language
  • a weak syllable
b : having little or no stress and obscured vowel sound
  • 'd in he'd is the weak form of would
9 : tending toward a lower price or value
  • a weak market
  • a weak dollar
10 : ionizing only slightly in solution
  • weak acids and bases



Examples of weak in a Sentence

  1. He has a weak throwing arm.

  2. The illness left her too weak to stand up.

  3. The child was born with weak lungs.

  4. The batter hit a weak ground ball.

  5. She uttered her reply in a weak voice.

  6. The door's hinge is weak.

Recent Examples of weak from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'weak.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of weak

Middle English weike, from Old Norse veikr; akin to Old English wīcan to yield, Greek eikein to give way, Sanskrit vijate he speeds, flees

Synonym Discussion of weak

weak, feeble, frail, fragile, infirm, decrepit mean not strong enough to endure strain, pressure, or strenuous effort. weak applies to deficiency or inferiority in strength or power of any sort.
    • felt weak after the surgery
feeble suggests extreme weakness inviting pity or contempt.
    • a feeble attempt to walk
frail implies delicacy and slightness of constitution or structure.
    • a frail teenager unable to enjoy sports
fragile suggests frailty and brittleness unable to resist rough usage.
    • a reclusive poet too fragile for the rigors of this world
infirm suggests instability, unsoundness, and insecurity due to old age or crippling illness.
    • infirm residents requiring constant care
decrepit implies being worn-out or broken-down from long use or old age.
    • the dowager's decrepit retainers

WEAK Defined for English Language Learners


Definition of weak for English Language Learners

  • : having little physical power or ability : not strong

  • : having little power or force

  • : likely to break or stop working properly : not able to handle weight, pressure, or strain

WEAK Defined for Kids


adjective \ ˈwēk \

Definition of weak for Students

weaker; weakest
1 : lacking strength of body, mind, or spirit
  • a weak smile
  • a weak patient
2 : not able to stand much strain or force
  • a weak rope
3 : easily overcome
  • a weak argument
4 : not able to function well
  • a weak heart
5 : not rich in some usual or important element
  • weak tea
6 : lacking experience or skill
  • He's a good reader, but is weak in math.
7 : not loud or forceful
  • a weak voice
8 : relating to or being the lightest of three levels of stress in pronunciation



Synonym Discussion of weak

weak, feeble, and frail mean not strong enough to stand pressure or hard effort. weak can be used of either a temporary or permanent loss of strength or power.
    • I felt weak after the operation.
    • I have weak eyes.
feeble implies very great and pitiful weakness.
    • A feeble dog wandered in the streets.
frail can be used of a person who since birth has had a delicate body.
    • Being a frail child I was always getting sick.

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