From Wiktionary, the free dictionary
ruck up (third-person singular simple present rucks up, present participle rucking up, simple past and past participle rucked up)
- To form untidy creases or folds in an article of clothing.
- (chiefly US, colloquial, idiomatic, somewhat vulgar) To be brave, to show some courage, to keep moving forward in a difficult situation.
