take unawares

"That's a good big fall to take unawares."

In such places it is better to use no bait, a little fish oil perhaps excepted, as you will then take unawares many a sly old fellow to whom a morsel of meat, no matter how cunningly arranged, would be simply a signboard of danger.

Sometimes her sudden rush would take unawares a full-fed gannet half-dozing on a rocky ledge.

The fame of his shameful doings had spread abroad, and it must soon come to the ears of the man whom he wished to take unawares.