letting off steam (verb) have a ball: have fun
Sinonime: alive, astir, attentive, careful, heedful, insomniac, insomnious, observant, on guard, on the alert, on the lookout, on the qui vive, sleepless, unsleeping, vigilant, waking, wary, watchful, wide-awake
Antonime: sleepy,
unaware