weak

adjective

• Lacking in force (usually strength) or ability.

  "The child was too weak to move the boulder."

• Unable to sustain a great weight, pressure, or strain.

  "a weak timber; a weak rope"

• Unable to withstand temptation, urgency, persuasion, etc.; easily impressed, moved, or overcome; accessible; vulnerable.

  "weak resolutions; weak virtue"

• Dilute, lacking in taste or potency.

  "We were served stale bread and weak tea."

• (grammar) Displaying a particular kind of inflection, including:
• That does not ionize completely into anions and cations in a solution.

  "a weak acid;  a weak base"

• One of the four fundamental forces associated with nuclear decay.
• Bad or uncool.

  "This place is weak."

• Having a narrow range of logical consequences; narrowly applicable. (Often contrasted with a strong statement which implies it.)
• Resulting from, or indicating, lack of judgment, discernment, or firmness; unwise; hence, foolish.
• Not having power to convince; not supported by force of reason or truth; unsustained.

  "The prosecution advanced a weak case."

• Lacking in vigour or expression.

  "a weak sentence; a weak style"

• Not prevalent or effective, or not felt to be prevalent; not potent; feeble.
• Tending towards lower prices.

  "a weak market; wheat is weak at present"

• Lacking contrast.

  "a weak negative"