What is the meaning of Weak?

Lacking in force (usually strength) or ability.

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

Limp, soft.

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

Having a strong, irrepressible emotional love for someone or (less often) something; sentimentally affected by such love.

Dilute, lacking in taste or potency.

Displaying a particular kind of inflection, including:

Regular in inflection, lacking vowel changes and having a past tense marked by /-d-/, /-t-/, or /-ð-/.

Showing less distinct grammatical endings.

Definite in meaning, often used with a definite article or similar word.

Related to, containing, or being a consonant which is prone to disappearing in some inflections, in most applicable languages including (but not limited to) w and y.

Related to, being, or containing the lenis consonant gradation, which resulted from historically closed syllables.

Of a form in which the accent tends to shift forwards (to the right, in transcription) or did so ancestrally in Proto-Indo-European, relative to the strong stem (which has the leftmost accent allowed).

In a grammatical case other than nominative, accusative, vocative or sometimes locative singular.

In a conjugation other than singular active forms (regardless of person, tense etc.).

Lenis, pronounced with less force or less markedness.

That does not ionize completely into anions and cations in a solution.

One of the four fundamental forces associated with nuclear decay.

Bad or uncool.

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.

Lacking in vigour or expression.

Not prevalent or effective, or not felt to be prevalent; not potent; feeble.

Tending towards lower prices.

Lacking contrast.

soft

Source: wiktionary.org