sightseeing vs looking

sightseeing and looking both are nouns.

Word	Noun	Adjective	Verb	Adverb
sightseeing	Yes	No	No	No
looking	Yes	Yes	No	No

As nouns, looking is a hypernym of sightseeing; that is, looking is a word with a broader meaning than sightseeing:

sightseeing: going about to look at places of interest
looking: the act of directing the eyes toward something and perceiving it visually; look

Other hypernyms of sightseeing include look, looking at.

sightseeing (noun)	looking (noun)
going about to look at places of interest	the act of searching visually
	the act of directing the eyes toward something and perceiving it visually; look

sightseeing (adjective)	looking (adjective)
	appearing to be as specified; usually used as combining forms