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1.
Military term refers to a ruck sack which is another name for a back pack. May also refer to all of ones personal web gear. To "ruck up" is grab your gear and go!
Ruck up soldiers were movin' out in five minutes!
by boss June 09, 2005
 
2.
A military phrase meaning to suck it up and drive on or walk it off.
WHAT?! Your feet hurt? Ruck up, Nancy!
by Soldierboy Jim November 07, 2013