Webster's Revised Unabridged Dictionary · 1913

Damp

Damp (damp) , noun

[Akin to LG., Dutch, & Danish damp vapor, steam, fog, German dampf, Icelandic dampi, Swedish damb dust, and to MNG. dimpfen to smoke, imp. dampf.]

1.
Moisture; humidity; fog; fogginess; vapor.
Night... with black air Accompanied, with damps and dreadful gloom. — Milton
2.
Dejection; depression; cloud of the mind.
Even now, while thus I stand blest in thy presence, A secret damp of grief comes o'er my soul. — Addison
It must have thrown a damp over your autumn excursion. — J. D. Forbes
3.
(Mining) A gaseous product, formed in coal mines, old wells, pints, etc.
Collocations (3)
Choke damp , a damp consisting principally of carbonic acid gas; -- so called from its extinguishing flame and animal life. See Carbonic acid, under Carbonic.
Damp sheet , a curtain in a mine gallery to direct air currents and prevent accumulation of gas.
Fire damp , a damp consisting chiefly of light carbureted hydrogen; -- so called from its tendence to explode when mixed with atmospheric air and brought into contact with flame.

Damp (damp) , adjective

1.
Being in a state between dry and wet; moderately wet; moist; humid.
O'erspread with a damp sweat and holy fear. — Dryden
2.
Dejected; depressed; sunk. [Rare]
All these and more came flocking, but with looks Downcast and damp. — Milton

Damp , intransitive verb

[Old English dampen to choke, suffocate. See Damp, n.]

1.
To render damp; to moisten; to make humid, or moderately wet; to dampen; as, to damp cloth.
2.
To put out, as fire; to depress or deject; to deaden; to cloud; to check or restrain, as action or vigor; to make dull; to weaken; to discourage.
To damp your tender hopes. — Akenside
Usury dulls and damps all industries, improvements, and new inventions, wherein money would be stirring if it were not for this slug. — Bacon
How many a day has been damped and darkened by an angry word! — Sir J. Lubbock
The failure of his enterprise damped the spirit of the soldiers. — Macaulay