to withhold or deny consent to do, enter into or upon, etc.; refuse

He declined to say more about it.

to express inability or reluctance to accept; refuse with courtesy

to decline an invitation; to decline an offer.

to cause to slope or incline downward.

Grammar .

to inflect (a noun, pronoun, or adjective), as Latin puella, declined puella, puellae, puellae, puellam, puella in the five cases of the singular.

to recite or display all or some subset of the inflected forms of a noun, pronoun, or adjective in a fixed order.

to express courteous refusal; refuse

We sent him an invitation but he declined.

to bend or slant down; slope downward; descend

The hill declines to the lake.

(of pathways, routes, objects, etc.) to follow a downward course or path

The sun declined in the skies.

to draw toward the close, as the day.

to fail in strength, vigor, character, value, etc.; deteriorate.

to fail or dwindle; sink or fade away

to decline in popularity.

to descend, as to an unworthy level; stoop.

Grammar . to be characterized by declension.

a downward slope; declivity.

a downward movement, as of prices or population; diminution

a decline in the stock market.

a failing or gradual loss, as in strength, character, power, or value; deterioration

the decline of the Roman Empire.

a gradual deterioration of the physical powers, as in later life or in disease

After his seventieth birthday he went into a decline.

progress downward or toward the close, as of the sun or the day.

the later years or last part

He became an editor in the decline of his life.