Antonyms of adj penal

2 of 3 senses of penal

Sense 2
penal -- (serving as or designed to impose punishment; "penal servitude")

INDIRECT (VIA punitive) -> rehabilitative -- (designed to accomplish rehabilitation; "from a penal to a rehabilitative philosophy"- J.B.Costello; "rehabilitative treatment")

Sense 3
penal, punishable -- (subject to punishment by law; "a penal offense")

INDIRECT (VIA illegal) -> legal -- (established by or founded upon law or official or accepted rules)

Similarity of adj penal

3 senses of penal

Sense 1
penal -- (of or relating to punishment; "penal reform"; "penal code")

Sense 2
penal -- (serving as or designed to impose punishment; "penal servitude")
       => punitive (vs. rehabilitative), punitory -- (inflicting punishment; "punitive justice"; "punitive damages")

Sense 3
penal, punishable -- (subject to punishment by law; "a penal offense")
       => illegal (vs. legal) -- (prohibited by law or by official or accepted rules; "an illegal chess move")