like clockwork Antonyms

accidentally from time to time aperiodically burdensomely challengingly demandingly discontinuously disorderedly disorganizedly distressfully effortfully episodically erratically at one time or another haphazardly at random arduously changeably chaotically difficultly inconstantly infrequently interruptedly irregularly laboredly sporadically sweatily toughly assiduously not without difficulty