tug vs bear on

tug is a noun but bear on is not a noun.

Word	Noun	Adjective	Verb	Adverb
tug	Yes	No	Yes	No
bear on	No	No	Yes	No

tug (noun)	bear on (noun)
a sudden abrupt pull
a powerful small boat designed to pull or push larger ships

tug (verb)	bear on (verb)
struggle in opposition	have an effect upon
pull hard	press, drive, or impel (someone) to action or completion of an action
pull or strain hard at	be relevant to
move by pulling hard	keep or maintain in unaltered condition; cause to remain or last
carry with difficulty
tow (a vessel) with a tug
strive and make an effort to reach a goal