Answer: floored

AnswerCrossword Clue
FLOORED

Knocked for a loop

FLOORED

Knocked down

FLOORED

Knocked one's socks off

FLOORED
Astounded
FLOORED
Bowled over
FLOOREDKnocked
FLOOREDPuzzled: Colloq.
FLOOREDNonplused: Colloq.
FLOOREDConfounded: Colloq.
FLOOREDConfounded
FLOOREDStruck dumb
FLOOREDStunned ... just stunned