LSJ
Ep. χελλύσσομαι, expectorate, (χέλυς II) Nic. Al. 81, Moer. p. 102 P. ; — Hsch. cites χελούειν, = βήσσειν (Lacon. or Boeot.). Act. χελλύσσω, metaph of a swimmer, spit out, i.e. the waves, Lyc. 727, cf. Sch. ad. loc.
Liddell-Scott-Jones, Greek-English Lexicon (9th ed., 1940)