tear-jerker (n.)

"fluid drop from the eye," Old English tear "tear, drop, nectar, what is distilled in drops," from earlier teahor, tæhher, from Proto-Germanic *tahr-, *tagr- (source also of Old Norse, Old Frisian tar, Old High German zahar, German Zähre, Gothic tagr "tear"), from PIE *dakru- (source also of Latin lacrima, Old Latin dacrima, Irish der, Welsh deigr, Greek dakryma).

To be in tears "weeping" is from 1550s. Tear gas is so called by 1917.

"to pull with sudden energy," 1580s; earlier "to lash, strike as with a whip" (1540s, surviving only in dialect), of uncertain origin, perhaps echoic. Intransitive sense of "make a sudden spasmodic motion" is from c. 1600. Compare Middle English yerkid, an adjective apparently meaning "pulled tight" (early 15c.), which has the form of a past participle. Also compare Middle English ferken "move hastily; drive (something) forward," from Old English fercian "to proceed." Related: Jerked; jerking.