He is said to have been a contemporary of Colmán of Lindisfarne who founded a monastery on the island in 665.
A site adjacent to the harbour on some old maps was called 'Guairim's Castle'; the presbytery is now located there.
Another site, listed on the Ordnance Survey maps as Áit Tigh Ghuairim was located in the townland of Bunamullen.
Guairim is supposed to have murdered six of Colmán's monks at Clossy Road, "over a question of tithes."
Guairim was taken to Renvyle and tried, then chained to a rock at low tide and left to drown.