How do you spell Cropper

Available Definitions:
1)  n. - One that crops.
2)  n. - A variety of pigeon with a large crop; a pouter.
3)  n. - A machine for cropping, as for shearing off bolts or rod iron, or for facing cloth.
4)  n. - A fall on one's head when riding at full speed, as in hunting; hence, a sudden failure or collapse.