fail, be spent, die, teireachduinn (inf.), Irish teiricim (O'Br.), Early Irish tarnic, it ended, from *tar-ic, transire (tar, across, and ic or nic of thig, thanig). Atkinson joins it with tairicim, arrive (= to-air-ic-), as in tàir, but the meanings scarcely suit.
Etymological dictionary of the Gaelic language.
Alexander Gairm Publications.
1982.