limit vs upper limit

limit and upper limit both are nouns.

Word	Noun	Adjective	Verb	Adverb
limit	Yes	No	Yes	No
upper limit	Yes	No	No	No

As nouns, upper limit is a hyponym of limit; that is, upper limit is a word with a more specific, narrower meaning than limit:

Other hyponyms of limit include edge, city limit, city limits, lower limit, three-mile limit.

limit (noun)	upper limit (noun)
the greatest possible degree of something	the limit on the upper (or northernmost) side of something
the boundary of a specific area	the largest possible quantity
as far as something can go
the greatest amount of something that is possible or allowed
the mathematical value toward which a function goes as the independent variable approaches infinity
final or latest limiting point

limit (verb)	upper limit (verb)
restrict or confine within limits
place limits on (extent or amount or access)
decide upon or fix definitely