bash (v.) Look up bash at Dictionary.com
"to strike violently," 1640s, perhaps of Scandinavian origin, from Old Norse *basca "to strike" (cognates: Swedish basa "to baste, whip, flog, lash," Danish baske "to beat, strike, cudgel"); or the whole group might be independently derived and echoic. Figurative sense of "abuse verbally or in writing" is from 1948. Related: Bashed; bashing.
bash (n.) Look up bash at Dictionary.com
"a heavy blow," 1805, from bash (v.). Meaning "an attempt" is attested by 1948. On a bash "on a drunken spree" is slang from 1901, which gave the word its sense of "party."