Definition of "Damn" :

noun: something of little value

"His promise is not worth a damn."

verb: wish harm upon; invoke evil upon

adjective: expletives used informally as intensifiers

"I'll be damned (or blessed or darned or goddamned) if I'll do any such thing."

adjective: used as expletives

"Oh, damn (or goddamn)!."

adverb: extremely