perfectly

adverbs

completely and without qualification; used informally as intensifiers
"an absolutely magnificent painting"; "a perfectly idiotic idea"; "you're perfectly right"; "utterly miserable"; "you can be dead sure of my innocence"; "was dead tired"; "dead right"
is derived from
in a perfect or faultless way
"She performed perfectly on the balance beam"; "spoke English perfectly"; "solved the problem perfectly"
antonym
is derived from