gorffwyllog

== Welsh == === Etymology === Cognate with Old Cornish gurbulloc. By surface analysis, gorffwyll +‎ -og. === Adjective === gorffwyllog (feminine singular gorffwyllog, plural gorffwyllog, equative mor orffwyllog, comparative mwy gorffwyllog, superlative mwyaf gorffwyllog) insane, mad, crazy Synonyms: gwallgof, lloerig manic, maniacal Synonyms: cynddeiriog, penboeth === Mutation === === Further reading === R. J. Thomas, G. A. Bevan, P. J. Donovan, A. Hawke, et al., editors (1950–present), “gorffwyllog”, in Geiriadur Prifysgol Cymru Online (in Welsh), University of Wales Centre for Advanced Welsh & Celtic Studies