Damn has 10 different meanings across 5 categories:
something of little value
"his promise is not worth a damn"
"not worth one red cent"
"not worth shucks"
The use of "damn" as a curse.
"Damn, I forgot my wallet at home again!"
In plain English: A damn is an act of cursing someone or something with strong anger.
"He let out a loud damn after dropping his keys down the drain."
Usage: Use "damn" as a noun to refer specifically to the act of cursing or swearing at someone or something. It functions as a countable term for an individual instance of profanity, often used in phrases like "that's one damn too many."
wish harm upon; invoke evil upon
"The bad witch cursed the child"
To condemn to hell.
"After ruining his chances at the competition, he felt like damn was all that deserved to happen to him."
In plain English: To damn someone means to declare them guilty of a serious sin or to condemn them to eternal punishment.
Usage: In everyday usage, to damn someone means to express strong disapproval or condemnation of their actions rather than literally sending them to hell. Use this verb when you want to criticize harshly without intending religious judgment.
expletives used informally as intensifiers
"he's a blasted idiot"
"it's a blamed shame"
"a blame cold winter"
"not a blessed dime"
"I'll be damned (or blessed or darned or goddamned) if I'll do any such thing"
"he's a damn (or goddam or goddamned) fool"
"a deuced idiot"
"an infernal nuisance"
Generic intensifier. Fucking; bloody.
"I am damn tired of waiting for the bus to arrive."
In plain English: Damn means terrible or awful when used to describe something bad.
"That was a damn good movie."
Usage: Use "damn" as an adjective to strongly emphasize a negative quality, such as calling something a "damn mess." It functions as an informal intensifier similar to "fucking" or "bloody" and should be placed directly before the noun it modifies.
extremely
"you are bloody right"
"Why are you so all-fired aggressive?"
Very; extremely.
"The damn heat outside made it impossible to even open a window."
In plain English: Damn is used to express strong anger, frustration, or surprise about something bad that just happened.
"The car broke down and I was damn lucky to still have gas in my tank."
Usage: Use "damn" as an adverb only in informal speech to intensify an adjective or another adverb, such as saying it is "damn cold." Avoid using it this way in formal writing or professional contexts where stronger synonyms like "extremely" are preferred.
Used to express anger, irritation, disappointment, annoyance, contempt or suprise, etc. See also dammit.
"I really need that report by noon and you haven't even started yet, damn it!"
The word comes from the Latin damnare, meaning "to condemn" or "inflict a loss." It traveled into English through Middle English and Old French while retaining its core sense of condemnation.