Complex sentence: A curtsey (also spelled curtsy) is a traditional gesture of greeting, predominantly done by women, in which the woman bows her head while bending her knees outward (rather than straight ahead), often sweeping one foot behind her.
Split into simpler sentences: A curtsey (also spelled curtsy) is a traditional gesture of greeting, in which a woman bends her knees while bowing her head. In more formal variants of the curtsey, the woman bends the knees outward (rather than straight ahead), often sweeping one foot behind her.