watchful

1. Engaged in or accustomed to close observation (synset 300092165)
   "caught by a couple of alert cops"; "alert enough to spot the opportunity when it came"; "constantly alert and vigilant, like a sentinel on duty"
   also:

   • wary - marked by keen caution and watchful prudence
   • awake - not in a state of sleep; completely conscious
   • lively - full of life and energy
   similar to:

   • argus-eyed, open-eyed, vigilant, wakeful - carefully observant or attentive; on the lookout for possible danger
   • fly - (British informal) not to be deceived or hoodwinked
   • heads-up, wide-awake - fully alert and watchful
   • lidless, sleepless - always watchful
   same as: alert
2. Experiencing or accompanied by sleeplessness (synset 300188664)
   "insomniac old people"; "insomniac nights"; "lay sleepless all night"; "twenty watchful, weary, tedious nights"
   similar to: awake - not in a state of sleep; completely conscious
   same as: insomniac, sleepless

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