Wide-mouthed, like the mouth of a sparrow: it is said of such persons, that they do not hold their mouths by lease, but have it from year to year; i.e. from ear to ear. One whose mouth cannot be enlarged without removing their ears, and who when they yawn have their heads half off.
SPARROW-MOUTHED
Meaning of SPARROW-MOUTHED in English
Slang English vocab. Английский сленговый словарь. 2012