厚礼 (hòulǐ): generous gift; lavish present

厚 ('thick, weighty') + 礼 ('gift, ritual') — a gift of substantial value or extraordinary courtesy. The phrase 厚礼相赠 ('to bestow a generous gift') sets a formal tone in business and diplomatic contexts. Compare 薄礼 (bólǐ, 'modest gift') — the polite-self-deprecating term you use when YOU give a present.

register

Slightly formal/written. In casual speech you'd say 大礼 (dàlǐ) for a 'big gift' or just 很贵的礼物. Common collocations: 送厚礼 (give a generous gift), 收厚礼 (receive a generous gift), 重金厚礼 ('heavy money and lavish gifts' — bribery overtones).