tearaway vs brainish

tearaway is a noun but brainish is not a noun.

Word	Noun	Adjective	Verb	Adverb
tearaway	Yes	Yes	No	No
brainish	No	Yes	No	No

As adjectives, tearaway and brainish are synonyms defined as:

tearaway and brainish: characterized by undue haste and lack of thought or deliberation

Other synonyms of tearaway include hotheaded, impetuous, impulsive, madcap.

tearaway (noun)	brainish (noun)
a reckless and impetuous person

tearaway (adjective)	brainish (adjective)
characterized by undue haste and lack of thought or deliberation	characterized by undue haste and lack of thought or deliberation