get behind

Short definition from Wiktionary

Verb

1. 1
   To come to believe or support something.
2. 2
   To support, to cheer on.
3. 3
   To appreciate, to enjoy.
4. 4
   To have a trip or any pleasurable experience with drugs.
5. 5
   To nag or pressure (somebody).
6. 6
   Used other than figuratively or idiomatically: see get, behind.