butt (v.)youdaoicibaDictYouDict
"hit with the head," c. 1200, from Anglo-French buter, from Old French boter "to push, shove, knock; to thrust against," from Frankish or another Germanic source (compare Old Norse bauta, Low German boten "to strike, beat"), from Proto-Germanic *butan, from PIE root *bhau- "to strike" (see batter (v.)). Related: Butted; butting. To butt in "rudely intrude" is American English, attested from 1900.
buttinski (n.)youdaoicibaDictYouDict
a jocular name for one who cuts into a line, etc., 1902, American English, from verbal phrase butt in (see butt (v.)) + surname ending based on Eastern European names.
buttinskyyoudaoicibaDictYouDict
"An interfering person", Early 20th century: from butt in (see butt) and -ski, formed in humorous imitation of the final element in many Russian names.