Answer: satup

AnswerCrossword Clue
SATUP

Postponed going to bed

SATUP

Began to take notice

SATUP

Waited (for) until long after dark

SATUP
Stopped lying
SATUP
... and took notice
SATUPPostponed bedtime
SATUPKept late hours
SATUPWaited for revelers to return
SATUPShowed interest or surprise
SATUPWas erect, as put
SATUPStayed awake
SATUPTook a sudden interest
SATUPKept a vigil
SATUPShowed surprise
SATUPShowed alertness
SATUPWatched the late TV
SATUPWatched the late show
SATUPWatched the late show.
SATUPWas alert.
SATUPPaid attention.
SATUPGot ready to face the day
SATUPGot out of a slump?
SATUPTook note
SATUPDidn't slouch
SATUPDid a doggie trick
SATUPDid a doggy trick
SATUPPartner of took notice
SATUPDisplayed sudden interest, in a way
SATUPShowed sudden interest, in a way
SATUPWas straight in the saddle
SATUPTook notice.
SATUPReacted to the teacher's entrance
SATUPCame to attention
SATUPSuddenly took interest, say
SATUPSuddenly took notice
SATUPSuddenly took interest
SATUPRose partially
SATUPAwaited someone's arrival before going to bed
SATUPPaid attention, so to speak
SATUPStopped slouching