Negative adverb used before verbs, adjectives, and other adverbs to indicate negation; also used as a bound-form prefix to form terms with opposite meanings

to enter; to go into; to move from outside to inside

a tiger's lair; used to describe a highly dangerous or hazardous place

(literary) how can one possibly; how could it be that; used to express a rhetorical question in formal writing

the offspring of a tiger