1 ratify, sanction, authorize, endorse, support, sustain, approve, uphold, back up, validate, verify, recognize; authenticate, accredit:
By-laws shall not take effect unless confirmed by the local authority.
2 establish, settle, affirm, ensure, clinch, substantiate, guarantee, bind, seal:
The king thereby confirmed his control over the islands.
3 strengthen, encourage, fortify, reinforce, corroborate, substantiate, buttress, prove:
Later events confirmed his opinion.