1. To work with or modify in a not particularly serious manner. "I diddled a copy of ADVENTso 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. The action or result of diddling. see also tweak, twiddle, frob. [Jargon File] (1995-01-31)