from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Attempting to include too wide a variety of things, typically with a result that is less functional than intended.
- adj. Of or pertaining to the kitchen sink drama; depicting social realities in an unstylized and direct manner.
From kitchen sink + -y. Sense 1 alludes to the phrase everything but the kitchen sink, sense 2 to the phrase kitchen sink realism. (Wiktionary)