booster vs friend

booster and friend both are nouns.

Word	Noun	Adjective	Verb	Adverb
booster	Yes	No	No	No
friend	Yes	No	No	No

As nouns, booster and friend are synonyms defined as:

Other synonyms of booster include admirer, champion, protagonist, supporter.

booster (noun)	friend (noun)
an additional dose that makes sure the first dose was effective	a person you know well and regard with affection and trust
the first stage of a multistage rocket	a person with whom you are acquainted
an amplifier for restoring the strength of a transmitted signal	an associate who provides cooperation or assistance
a thief who steals goods that are in a store	a person who backs a politician or a team etc.
someone who is an active supporter and advocate
a person who backs a politician or a team etc.