travailous

The story

1. Old French · derived fromtravaillos“tiring, painful”
2. Anglo-Norman · derived fromtravaillous
3. Middle English · inherited fromtravailous“laborious, wearisome”
4. English todaytravailous

From Middle English travailous (“laborious, wearisome”), from Anglo-Norman travaillous, Old French travaillos (“tiring, painful”). Equivalent to travail + -ous.