IPA: /ˈɡrʌm.bli/
KK: /ˈɡrʌm.bli/
Tending to complain or express dissatisfaction in a low voice.
He was feeling grumbly after waiting in line for so long.
Grumbly → The word is derived from the verb 'grumble' (of uncertain origin, possibly imitative of the sound of grumbling) with the suffix '-y' (meaning characterized by). The term 'grumbly' describes a state characterized by grumbling or complaining.
Think of the sound of someone 'grumbling' — that's why 'grumbly' means someone who is characterized by complaining.