What is another word for "pledge"?

Roget's Thesaurus (1911) lists these synonyms for "pledge": abide, abnegation, abstain, abstainer, abstemious, abstemiousness, abstinence, abstinent, acknowledge, acknowledgment, acquiescence, acquit, acquittal, acquittance, act, adhere, adhesion, alcoholic, all, amusement, and, anniversary, arch, are, artillery, band, bonfire, calf, carry, celebrate, celebrated, celebration, ceremony, chair, china, cling, comes, commemorate, commemoration, commemorative.