To dismiss any expression of solidarity, anti-racism, objection to misogyny etc as "virtue-signalling".

Vermin-signalling is simultaneously an attempt to discredit the views - most likely in favour of a minority group - that are being expressed, while underlining the dominance of the "correct" group, and an efficient method of establishing that you hold utterly verminous views that will probably mean your family slowly stop talking to you on Facebook or even coming round for Thanksgiving.

A term used to reference cannabis/marijuana/weed.

Definition:

verb. adj. The act or quality of another act that describes the signalling (typically quoting with annotation on social media) to the broader audience that vermin (a stupid person or person(s) responsible for a stupid action) has been identified.

History:
An illogical compound adjective that was most likely originally made up by some social media tryhard whom has little regard for grammatical qualities. Please refer to the original definition posted on Urban Dictionary to admire the irony.