It's not bad for a minisite; I doubt you'd ever sell this name to a domainer or end user, but it is the umbrella term that covers a category of clothing. The phrase 'plus size special occasion' only gets 1300 exact monthly searches, but related full terms like 'plus size special occasion dresses' can get many more (that one gets 8800 searches, dn is taken in a few extensions).
If you are into minisites, I'd build a site for this, with adsense and an Amazon store. It wouldn't make a lot of cash, but developed properly as a small site it should be worth it. If you're not into minisites, I'd get a refund for the name and drop it.