To rise up; of animals fur or hair; as in fear.

ETYM Perhaps of different origin from ruffle to wrinkle; cf. od. roffeln, roffen, to pander, lg. raffein, Dan. ruffer a pimp. Related to Rufflan.
1. To disturb the smoothness of; SYN. ruffle up, rumple, mess up.
2. To erect or fluff up; SYN. fluff.
3. To pleat or gather into a ruffle; SYN. pleat.
4. To trouble or vex.