That may be complained of.

(Singapore, colloquial) A dissatisfied male who always grumbles or rants, and reports on others’ faults usually to someone in authority or the media, with or without ill intentions.

plural of complain king

plural of complain queen

(Singapore, colloquial) A woman who is constantly dissatisfied and always grumbles or reports faults of others to authorities or the media, with or without ill intentions.

I have nothing to complain about; everything is okay with me.

(humorous) Said as a mild admonishment to somebody who is always complaining.

In a complaining manner; peevishly.

The quality of being complaining.