double over vs double up

double over and double up both are verbs.

Word	Noun	Adjective	Verb	Adverb
double over	No	No	Yes	No
double up	No	No	Yes	No

As verbs, double over and double up are synonyms defined as:

double over and double up: bend over or curl up, usually with laughter or pain

Other synonyms of double over include double.

double over (verb)	double up (verb)
bend over or curl up, usually with laughter or pain	stake winnings from one bet on a subsequent wager
	bend over or curl up, usually with laughter or pain
	share a room or a bed designed for only one person