The adverb arbitrarily describes something that's done haphazardly, based on random chance or on your own whim of the moment. ... When there's not much reason behind your actions, they're done arbitrarily.

What type of word is arbitrary?

undetermined; not assigned a specific value: an arbitrary constant. noun, plural ar·bi·trar·ies.

What is the adverb form of arbitrary?

arbitrarily. In an arbitrary manner. To an arbitrary degree.