[nq:1]I have a list of words/expressions whose meaning I cannot clearly find.. [/nq] To "get behind" here signifies give active support to; I imagine the metaphor is people getting behind some heavy thing (such as a laden cart) to help push it along. [nq:1]to bail on sb[/nq] "Bail on" here is short for "bail out on", which is a term signifying a rapid departure, typically from a potentially disastrous situation ( a test pilot bails out of a burning airplane); in modern slang, "bail on" has slightly weakened to mean simply to hastily abandon (a person or cause) the element of pending disaster from remaining has disappeared.
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