Wiktionary
complainingly
adv. In a complaining manner; peevishly.
WordNet
complainingly
adv. with complaints; "she did her work, but she did so complainingly" [ant: uncomplainingly]
Usage examples of "complainingly".
MR CHAIRMAN:--Some if not all the gentlemen on the other side of the House who have addressed the committee within the last two days have spoken rather complainingly, if I have rightly understood them, of the vote given a week or ten days ago declaring that the war with Mexico was unnecessarily and unconstitutionally commenced by the President.
The local gardener was trudging complainingly beside Albertine along the walk.