noun

the action or fact of carrying out a task clumsily or incompetently.

he was heavily criticized for his bungling of the case

adjective

making or characterized by many clumsy mistakes.

the work of a bungling amateur

incompetent,blundering,amateurish,inept,unskilful,inexpert,clumsy,maladroit,gauche,awkward,inefficient,muddled,oafish,clodhopping,bumbling,stumbling,lumbering,foolish,useless,ham-fisted,ham-handed,cack-handed