hike vs hike up

hike is a noun but hike up is not a noun.

Word	Noun	Adjective	Verb	Adverb
hike	Yes	No	Yes	No
hike up	No	No	Yes	No

As verbs, hike and hike up are synonyms defined as:

Other synonyms of hike include boost.

hike (noun)	hike up (noun)
a long walk usually for exercise or pleasure
the amount a salary is increased
an increase in cost

hike (verb)	hike up (verb)
walk a long way, as for pleasure or physical exercise	pull up
increase	increase