1845, American English, clipped form of bachelor (n.). Also in colloquial American English use as a verb (1870) meaning "to live as an unmarried man," especially "to do one's own cooking and cleaning." Related: Bached; baching.
A bachelor (1850s+)verb
(also bach it) Of a man, to live alone (1860s+)
To enjoy the life of a bachelor: With his wife on a trip, he bached it for a week