Definition of side-of-the-mouth in English:

side-of-the-mouth

adjective

  • Designating a mode of speech in which words are uttered from the side of the mouth, typically in a thick drawl; designating a remark made in this manner. Also in extended use, designating a richly colloquial style of speech or writing.

Origin

1930s; earliest use found in The Chronicle-Telegram. From side + of + the + mouth.

Pronunciation

side-of-the-mouth

/ˌsʌɪdə(v)ðəˈmaʊθ/