not know (one's) own strength

(redirected from doesn't know his own strength)

not know (one's) own strength

To underestimate how much force one is able to apply or exert in some physical activity. A: "Hey, you're pushing the car too fast! I just need to get it off the road, not down into the ditch!" B: "Oops, sorry. Guess I don't know my own strength!" You need to be more careful with that equipment. You don't know your own strength!
See also: know, not, own, strength
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

not know one's own strength

not to realize how destructive or harmful one's strength can be. I didn't mean to hurt you. I guess I don't know my own strength. He might break the door down by accident. He doesn't know his own strength and could end up pushing too hard against the door.
See also: know, not, own, strength
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
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References in periodicals archive ?
Yes, you get the occasional Tiggerish lad with bundles of energy, the sort who doesn't know his own strength and ends up bashing his way around the playground.
He doesn't know his own strength, which can cause problems when he's playing with other children - he sends the other lads flying.
Even if he doesn't know his own strength when it comes to football.
People won't let him because he'll just spoil things; he's too stupid and he doesn't know how to do that; he'll just hurt himself; he might hurt others; he doesn't know his own strength," Johnston told Windspeaker during a promotional stop in Calgary.
He doesn't know his own strength and almost breaks your fingers whenever he shakes hands.
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