Diddy/ˈdɪdi/ Definition 1 of 2Pro Tip 1/3British Slang Used commonly in the UK, 'diddy' adds friendly emphasis to smallness. He moved into a diddy flat near the market. Pro Tip 2/3Emphasize Petite 'Diddy' often conveys affection or endearment when referring to something small. Look at those diddy shoes for the baby! Pro Tip 3/3Informal Use Appropriate for casual conversation but not in formal or academic contexts. I only need a diddy bit of sugar in my tea.