Old English swin "pig, hog," from Proto-Germanic *swinan (cf. Old Saxon, Old Frisian Middle Low German, Old High German swin, Middle Dutch swijn, Dutch zwijn, German Schwein), neuter adjective (with suffix *-ino-) from PIE *su- (see sow (n.)). The native word, largely ousted by pig. Applied to persons from late 14c. Phrase pearls before swine (mid-14c.) is from Matt. vii:6; an early English formation of it was:
Ne ge ne wurpen eowre meregrotu toforan eo wrum swynon. [c.1000]
The Latin word was confused in French with marguerite "daisy" (the "pearl" of the field), and in Dutch the expression became "roses before swine."