Antonyms of adj crackbrained

1 sense of crackbrained

Sense 1
crackbrained, idiotic -- (insanely irresponsible; "an idiotic idea")

INDIRECT (VIA insane) -> sane -- (mentally healthy; free from mental disorder; "appears to be completely sane")

Similarity of adj crackbrained

1 sense of crackbrained

Sense 1
crackbrained, idiotic -- (insanely irresponsible; "an idiotic idea")
       => insane (vs. sane) -- (afflicted with or characteristic of mental derangement; "was declared insane"; "insane laughter")