pants

beat the pants off: seebeat.

by the seat of your pants by instinct rather than logic or knowledge. informal

☞ This expression was first used by pilots in the mid 20th century, in the form fly by the seat of your pants, meaning 'fly a plane by relying on human judgement rather than navigational instruments'.

1977Martin WalkerNational Front Mussolini had governed by the seat of his pants, guided in part by his early Socialism, in part by his…bombastic nationalism.

catch someone with their pants (or trousers) down catch someone in an unprepared state or sexually compromising situation. informal

have ants in your pants: seeant.

a kick in the pants: seekick.

scare (or bore etc.) the pants off someone make someone extremely scared, bored, etc. informal

wearing (or in) short pants very young. informal

☞ A little boy was traditionally dressed in shorts before attaining a certain age, when he would be allowed to wear long trousers.