To make something more complex; to complicate.
To make deep or deeper
To make more sound or heavy.
To become lower in tone
To make darker or more intense; to darken
To become deeper
To become more intimate.
To make lower in tone
To become darker or more intense
To become more thorough or extensive.
To make more thorough or extensive.
To become more sound or heavy.
To make more intimate.
To make more poignant or affecting; to increase in degree