{v. phr.}, {slang} To make a mistake. * /I must have been slipping a cog when I said that I would run for mayor./ * /Jim hates to sleep outdoors. He's slipping his gears if he's promised to take the boys camping./ Compare: SLIP UP.
SLIP A GEAR
Meaning of SLIP A GEAR in English
Slang English vocab. Английский сленговый словарь. 2012