Antonyms of adj on

2 senses of on

Sense 1
on (vs. off) -- (in operation or operational; "left the oven on"; "the switch is in the on position")

off (vs. on) -- (not in operation or operational; "the oven is off"; "the lights are off")
        => disconnected -- (not plugged in or connected to a power source; "the iron is disconnected")

Sense 2
on (vs. off) -- ((of events) planned or scheduled; "the picnic is on, rain or shine"; "we have nothing on for Friday night")

off (vs. on), cancelled -- ((of events) no longer planned or scheduled; "the wedding is definitely off")

Similarity of adj on

2 senses of on

Sense 1
on (vs. off) -- (in operation or operational; "left the oven on"; "the switch is in the on position")
       => connected -- (plugged in; "first check to see whether the appliance is connected")

Sense 2
on (vs. off) -- ((of events) planned or scheduled; "the picnic is on, rain or shine"; "we have nothing on for Friday night")

Synonyms of adv on

3 senses of on

Sense 1
along, on -- (with a forward motion; "we drove along admiring the view"; "the horse trotted along at a steady pace"; "the circus traveled on to the next city"; "move along"; "march on")

Sense 2
on -- (indicates continuity or persistence or concentration; "his spirit lives on"; "shall I read on?")

Sense 3
on -- (in a state required for something to function or be effective; "turn the lights on"; "get a load on")