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.
BRONZER, FOUNDATION, LINER, and STAIN are all types of makeup or cosmetic products.
BEAR, BED, GOLDILOCKS, and PORRIDGE are all things featured in the story of Goldilocks and the Three Bears.
FIBERGLASS (glass), SILVERSTEIN (stein), SMUG (mug), and STUMBLER (tumbler) all end with words that are drinking vessels.
GOREY (gory), GRIMM (grim), GRIZZLY (grizzly means fierce/brutal), and SCARRY (scary) are homophones or near-homophones of words meaning brutal/frightening, and are also surnames of famous children's authors (Edward Gorey, Brothers Grimm, Shel Silverstein's peer Richard Scarry).