businesslike vs earnest

businesslike is not a noun while earnest is a noun.

Word	Noun	Adjective	Verb	Adverb
businesslike	No	Yes	No	No
earnest	Yes	Yes	No	No

As adjectives, businesslike and earnest are synonyms defined as:

businesslike and earnest: not distracted by anything unrelated to the goal

businesslike (noun)	earnest (noun)
	something of value given by one person to another to bind a contract

businesslike (adjective)	earnest (adjective)
exhibiting methodical and systematic characteristics that would be useful in business	not distracted by anything unrelated to the goal
not distracted by anything unrelated to the goal	characterized by a firm and humorless belief in the validity of your opinions
	sincerely earnest