1 noun ZOOL of animalbolg masc1 c m uit has a white underbellytá bolg bán air2 noun AERO of aircraft etcíochtar masc1 c m uthe underbelly of an aeroplaneíochtar eitleáin3 noun literary underworldthe seedy underbelly of the cityan taobh gránna den chathair4 noun literary vulnerable partthe soft underbelly of the gangball bog na droinge