party-crashing1
/ˈpɑːtɪˌkraʃɪŋ/informal (originally and chiefly North American )
noun
The action of attending a party or other gathering without an invitation.
Origin
1930s; earliest use found in Ogden (Utah) Standard Examiner. From party + crashing.
party-crashing2
/ˈpɑːtɪˌkraʃɪŋ/informal (originally and chiefly North American )
adjective
Of a person: that attends a party or other gathering without an invitation; that gate-crashes.
Origin
1940s; earliest use found in The Chicago Tribune. From party + crashing.