backstroke

noun

1. A backhanded stroke or blow.

   “He observed that Cid Ruy-dias was an excellent knight; but not equal to the Lord of the Flaming-sword, who with one back-stroke [translating revés] had cut two fierce and monstrous giants through the middle.”

2. A stroke swum lying on one's back, while rotating both arms through the water as to propel the swimmer backwards.
3. The pull on the tail of the rope that swings the bell through a full circle (compare handstroke)

verb

1. To swim the backstroke.