slip a cog

Idioms  

1. Also,. Lose one's ability to reason soundly or make correct judgments, as in She must have slipped a cog or she would never have gone out barefoot in December, or What's the matter with him? Has he slipped his gears? These slangy usages allude to a mechanical failure owing to the cog of a gear or a gear failing to mesh. The first dates from about 1930, the variant from the 1960s.

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Example Sentences

And would nature allow it to choke up or slip a cog just because a little thing like a worm got tangled in its gearing?

From Project Gutenberg

I will try to answer your questions, but you know after a lapse of forty years, one’s memory may slip a cog.

From Project Gutenberg

On the second round, he seemed to slip a cog on the par-three fifth hole.

From Time Magazine Archive

I know you can drive like—like you can work algebra, logyruthms, and never slip a cog.

From Project Gutenberg

The best I can think of him is that losing his savings may have made him slip a cog, and then the scare over the way we landed here and his spells of fever probably hurried up the softening.”

From Project Gutenberg