Phrasal Verbs with UP & DOWN

Verb withdraw from a position, opinion, or commitment.
back down
While the Mexican Hairless Dog, as it's known in English speaking countries, is noted for having a calm demeanor, they are exceptional guard dogs and will not back down from a fight.
Verb support or confirm
Taekwondo has no standard system for collecting or classifying statistics that go beyond the final score. Fans can argue about who has the most effective roundhouse kick, but don't have any numbers to back up their claims.
Verb laugh or cause to laugh hilarously or uncontrollably
crack up
Watch Jimmy Fallon and Bryan Cranston crack up while playing a game called "Word Sneak," in which they have to sneak incongruous words casually into a conversation.
Noun serious attempt to punish people for doing something that is not allowed
A Vietnamese court sentenced a dissident blogger to 15 months in prison for posting online criticism of the government, the latest case in an intensifying crackdown against dissent in the one-party communist country.
Verb totally enjoy oneself
get down
Watch Snowball, the dancing cockatoo, get down to music. He has the beat and amazing dance moves too!
Verb wake and rise from one's bed
When you get up in the morning, different parts of the brain spring into action at different rates. This period of grogginess is called "sleep inertia," and it's why we sometimes wake up unsure of where we are.