gibbering is a grammatical form of:
gibber gibbering
brilléiseach adjgliograch adj1 a gibbering old fool seanamadán gliograch, seanamadán gan chiall, seancheolán I thought she was a gibbering idiot shíl mé nach raibh splinc mheabhrach inti, mheas mé nár óinseach go dtí í, cheap mé nach raibh inti ach baothán ina seasamh Loading phrases and examples...