Definition of "frowning"

Frowning heads are still gloomily shaken when the subject is raised on the NER, [...].

1964 September, G. Freeman Allen, “Interim report on the East Coast Route express service”, in Modern Railways, page 160

Let all the creatures above and below frown and scowl upon me; if my Creator smile, I am happy; nor can all their frownings diminish my complete joy.

1734, Isaac Watts, Reliquiæ juveniles