Where does “géilsinecht” come from?

géilsinecht (Old Irish) comes from Old Irish géilsine, from Old Irish -sine — Forms abstract nouns from other nouns.

Ancestry of “géilsinecht”, step by step

StepLanguageWordMeaning
1Old Irishgéilsinehostageship, rendering of hostages
2Old Irish-sineForms abstract nouns from other nouns
Every word from Old Irish -sine →Every word from Old Irish géilsine →