Longman Dictionary of Contemporary English
The Collaborative International Dictionary
off-guard \off-guard\ pred. adj. not watching for possible danger; not alert; as, caught in an off-guard moment.
Wiktionary
a. (alternative spelling of off guard English)
WordNet
adj. not prepared or vigilant; "the blow caught him napping"; "caught in an off-guard moment"; "found him off his guard" [syn: napping, off-guard(a), off guard(p), off one's guard(p), off his guard, off her guard, off your guard]
Usage examples of "off-guard".
He liked to tease Nurse Edna and Nurse Angela in the operating room, where the subject of the soul could catch the dear nurses off-guard.
He himself had been caught off-guard from the first, but the lizardman did not seem at all surprised.
Micah tried a little smoothness of his own, and it caught Rush off-guard.
In the same moment of time Belinda flung herself back against an off-guard Trudi, who staggered backwards, teetered on the edge of the loading sill, then fell from sight.
It was a smell loaded with nostalgia, and for once Penelope found herself caught off-guard, and was suffused with a mindless ecstasy that she had not known since she was a child.
Now here was the strain of a constant vigilance as these tireless Yangs watched for an off-guard moment.
But, at moments when she was off-guard, as when Zimmermann consulted his watch, it leapt at her with unabated strength.