peacthach
Definitions (by source)
sinner, 888; ai. -thaigh 929, -caidh 935, 1139, -caigh 1097; gi. peacthach 1233, 1287; ti. -thachaibh 884.
An Teagasg Críosdaidhe. Editor: Fearghal Mac Raghnaill, O.F.M.
m., sinner, 587; gen. –thaigh, 1415-19; pl. –thaigh, 520
Trí Bior-Ghaoithe an Bháis: The Three Shafts of Death. Editor: Osborn Bergin.