tying up vs docking

tying up and docking both are nouns.

Word	Noun	Adjective	Verb	Adverb
tying up	Yes	No	No	No
docking	Yes	No	No	No

As nouns, tying up and docking are synonyms defined as:

Other synonyms of tying up include dockage, moorage.

tying up (noun)	docking (noun)
the act of securing an arriving vessel with ropes	the act of securing an arriving vessel with ropes