underwrite

The story

1. Old English · inherited fromunderwrītan“to write at the foot of, write under, subscribe”
2. Middle English · inherited fromunderwriten
3. English todayunderwrite

From Middle English underwriten, from Old English underwrītan (“to write at the foot of, write under, subscribe”). Compare Dutch onderschrijven (“to endorse”), German unterschreiben (“to sign; endorse”), Danish underskrive (“to sign; endorse”). By surface analysis, under- + write.