frivolous action
noun[CorU]
LAWukus(alsovexatious action)alegalactionthat is notbasedonseriousfacts, but is oftenstartedinordertoembarrassorannoythedefendant(=personorcompanyaccused), and is notlikelytosucceed:
Heavycostswereawardedagainst thecompanyfor afrivolousaction.