• 賛成さんせい — approval; agreement
• 協賛きょうさん — sponsorship; cooperation
• 賛美さんび — praise; glorification
• 賞賛しょうさん — admiration; acclaim
• 絶賛ぜっさん — high praise
• 賛辞さんじ — words of praise

賛 comes from the older form 贊 plus 貝 (shell/money), carrying the idea of adding support or value—hence its use for agreement, endorsement, and praise.

彼かれの 意見いけんに 賛成さんせいです。
I agree with his opinion.

その映画えいがは 絶賛ぜっさんされた。
The movie was highly praised.