Antonyms of adj amateurish

1 sense of amateurish

Sense 1
amateurish, amateur, inexpert, unskilled -- (lacking professional skill or expertise; "a very amateurish job"; "inexpert but conscientious efforts"; "an unskilled painting")

INDIRECT (VIA unprofessional) -> professional -- (characteristic of or befitting a profession or one engaged in a profession; "professional conduct"; "professional ethics"; "a thoroughly professional performance")

Similarity of adj amateurish

1 sense of amateurish

Sense 1
amateurish, amateur, inexpert, unskilled -- (lacking professional skill or expertise; "a very amateurish job"; "inexpert but conscientious efforts"; "an unskilled painting")
       => unprofessional (vs. professional) -- (not characteristic of or befitting a profession or one engaged in a profession; "described in unprofessional language so that high school students could understand it"; "was censured for unprofessional conduct"; "unprofessional repairs")