verb

• (transitive) To make deep or deeper
• (transitive) To make darker or more intense; to darken
• (transitive) To make more poignant or affecting; to increase in degree
• (transitive) To make lower in tone
• (transitive) To make more thorough or extensive.
• (transitive) To make more intimate.
• (transitive) To make more sound or heavy.
• (intransitive) To become deeper
• (intransitive) To become darker or more intense
• (intransitive) To become lower in tone
• (intransitive) To become more thorough or extensive.
• (intransitive) To become more intimate.
• (intransitive) To become more sound or heavy.