Wiktionary
n. (context idiomatic singulare tantum English) A solution or scenario which combines the disadvantages of two opposed prior solutions, often having been intended to combine their benefits instead.
Usage examples of "worst of both worlds".
He lay on his own, immaculate bed, which he carefully made each morning out of habit from many years on the Enterprise (under his mother's critical gaze: Starfleet tautness and hospital corners--the worst of both worlds).
Hovering over the person she'd entrusted a task to only bought the worst of both worlds.
It seemed to Jay Omega that he had the worst of both worlds-another reason that the English department made him uneasy.
So KDD has managed to get the worst of both worlds: it is viewed both as a big sinister monopoly and as a cringing sidekick to the even bigger and more sinister AT&.
Which, she conceded silently to Aburish, gave her the worst of both worlds.