1) Certain dagger 2) Dagger of old Ireland 3) Dagger or dirk 4) Double-edged dagger 5) Gaelic dagger 6) Old dagger 7) Old Irish dagger 8) Old Irish hunting knife 9) Scottish dirk Found on https://www.crosswordclues.com/clue/skean
Skean noun [ Ir sgian ; akin to Gael. sgian , W. ysgien a large knife, a scimiter.] A knife or short dagger, esp. that in use among the Highlanders of Scotland. [ Variously spelt.] 'His skean , or pistol.' Spenser. Found on http://www.encyclo.co.uk/webster/S/112