Curtsey is a gesture of respect or deference, usually performed by bending one's knee and bowing the head. The term curtsey is derived from the French word courteous, which means to bow. The two crossword solutions, bobbed (6 letters) and knelt (5 letters), both refer to the same action of bending one's knee and bowing the head. Bobbed is a more informal version of the gesture, while knelt is a more formal version.