Wiktionary
kick pleat
n. A kind of pleat that is set near the hem of a straight skirt to allow the wearer to walk comfortably while preserving the narrow style line.
WordNet
kick pleat
n. pleat in back of a straight skirt to allow ease in walking
Usage examples of "kick pleat".
He saw the kick pleat of the girl's skirt shift again as she stepped into the van.
She had not seen his look, but she had seen the shift in the kick pleat, what it revealed, and understood it perfectly.