double up

Wiktionary

1. v. transitive To double the quantity, amount or duration of something
2. v. poker, by extension, intransitive To double one's amount of chips by winning an all-in pot.
3. v. To bend, bend over; to fold; to stoop.
4. v. intransitive To have a secondary use.
5. v. baseball, transitive To get the second out in a double play, typically referring to getting an out by beating a runner back to a base (often by throwing) after a fly ball has been caught
6. v. intransitive To employ double the usual resources for a particular purpose.

WordNet 3.0

1. v. stake winnings from one bet on a subsequent wager
2. v. bend over or curl up, usually with laughter or pain
3. v. share a room or a bed designed for only one person