What does weak mean?
Weak is an adjective meaning deficient in strength, power, intensity, or effectiveness. It can describe a person who lacks physical energy, an argument supported by little evidence, a structure unable to bear much weight, or a liquid that is unusually light or diluted. The word also carries social and moral overtones: calling a person weak may suggest lack of resolve, confidence, or character, while describing an argument as weak is usually a measured criticism of its evidence or reasoning. In everyday use, weak contrasts with strong but can be more specific than feeble, which often suggests marked physical weakness, or flimsy, which emphasizes an obviously insubstantial structure. Weak is useful because it identifies deficiency in many different areas while allowing the context to determine whether the implication is physical, intellectual, emotional, or merely insufficient in degree.
adjectiveLacking physical, mental, or moral strength; not strong, forceful, or effective.
- Lacking physical strength or energy.
- Insufficient in strength, power, intensity, or effectiveness.
- Lacking moral resolve, intellectual ability, or confidence.
- Tentative, uncertain, or easily influenced.
- Light or diluted, as in weak tea or a weak solution.
"The old bridge was too weak to support the weight of the trucks."
"The injured athlete felt too weak to continue."
"Her explanation was persuasive, but the evidence remained weak."
The word weak is an old one: it entered English as wac, whose meanings included both “lacking strength” and “soft or tender,” showing how closely weakness and vulnerability are connected.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of weak
Weak comes from Old English wac, an adjective meaning “weak, tender, or soft.” It developed through Middle English forms related to the modern spelling and belongs to the Germanic family, with cognates including Dutch zwak, German schwach, and Icelandic veikur. The English word has long conveyed both physical insufficiency and vulnerability or lack of force.
Related word forms
How weak is actually used
Weak can describe physical strength, sound, light, liquids, arguments, or a person's character. In formal contexts it may sound blunt or dismissive, especially when applied to a person, so descriptions of ability or conduct are often more precise.
Easily confused with weak
Weak and week are pronounced the same, but week means a period of seven days.