All 16 words, sorted alphabetically. Group them into four categories of four.
The four category names, easiest to hardest. No words revealed yet.
Theme name plus one word from each category.
3 BALL (red in billiards), CARDINAL (the red-robed church official/red bird), HEART EMOJI (depicted in red), and SOLO CUP (iconic red party cup) are all famously red.
8 BALL (behind the 8 ball = in trouble), DEEP END (in over your head), LIMB (out on a limb = risky position), and THIN ICE (on thin ice = precarious situation) are all used in metaphors for dangerous or precarious situations.
These are musical artists with their starting numbers removed: 6 MAFIA (Three 6 Mafia), CHAINZ (2 Chainz), DIRECTION (One Direction), NON BLONDES (4 Non Blondes).
COUTH (South with S→C), FORTH (North with N→F), LEST (West with W→L), OAST (East with E→O) are all cardinal directions with the first letter changed to a different letter.