drop_the_ball, sin, blunder, boob, goof
Meaning: commit a faux pas or a fault or make a serious mistake; "I blundered during the job interview"
But Kerensky made a fatal blunder.
It is only nature makes the blunder of giving the sharpest swords the weakest scabbards.
"It was the only place I could think of your Majesty," added the Soldier, fearing he had made a blunder.
She was so abashed at her blunder, that she looked absolutely imploring, and Mr. Denis Oglethorpe smiled again.
"One of the lower-deck loading ports could be left unlocked, by carelessness, and he could blunder overboard at about five thousand feet." He watched Harrington make a deceptively pointless-looking move.
Here, however, the light was invisible, and Sarka flew on in fear that somehow his aircars would blunder into it, and be destroyed--for that the blue light was an agent of ghastly destruction became instantly apparent.
It so happened, too, that just that instant there was not a sound in the room, so everyone heard the blunder. General Phillips straightened back in his chair, and his little son gave a smothered giggle--for which he should have been sent to bed at once. But that was not all!