diddle 1. vt. To work with or modify in a not particularly serious manner. "I diddled a copy of {ADVENT} so it didn't double-space all the time." "Let's diddle this piece of code and see if the problem goes away." See {tweak} and {twiddle}. 2. n. The action or result of diddling. See also {tweak}, {twiddle}, {frob}.