Nearly
Part of speech: adverb
Definition: almost, but not quite; slightly short of intimately
Example sentence: Summer nearly does me in every year. It's too hot and the light is unforgiving and the days go on way too long.
Nigh
Part of speech: verb
Definition: To draw nigh (to); to approach; to come near.
Part of speech: preposition
Definition: near; close to
Part of speech: adverb
Definition: almost, nearly
Part of speech: adjective
Definition: near, close by
Example sentence: The ability to express an idea is well nigh as important as the idea itself.