Antonyms of adj restless

3 senses of restless

Sense 1
restless, ungratified, unsatisfied -- (worried and uneasy)

INDIRECT (VIA discontented) -> contented, content -- (satisfied or showing satisfaction with things as they are; "a contented smile")

Sense 2
restless -- (ceaselessly in motion; "the restless sea"; "the restless wind")

INDIRECT (VIA moving) -> nonmoving, unmoving -- (not in motion)

Sense 3
restless (vs. restful), uneasy -- (lacking or not affording physical or mental rest; "a restless night"; "she fell into an uneasy sleep")

restful (vs. restless), reposeful, relaxing -- (affording physical or mental rest; "she spent a restful night at home")
        => slumberous, slumbrous -- (quiet and tranquil; "a slumberous June morning")

Similarity of adj restless

3 senses of restless

Sense 1
restless, ungratified, unsatisfied -- (worried and uneasy)
       => discontented (vs. contented), discontent -- (showing or experiencing dissatisfaction or restless longing; "saw many discontent faces in the room"; "was discontented with his position")

Sense 2
restless -- (ceaselessly in motion; "the restless sea"; "the restless wind")
       => moving (vs. nonmoving) -- (in motion; "a constantly moving crowd"; "the moving parts of the machine")

Sense 3
restless (vs. restful), uneasy -- (lacking or not affording physical or mental rest; "a restless night"; "she fell into an uneasy sleep")