green group · The short answer
DOUBLE VOWELS
Each puzzle word passes the same exact test. The four mappings show how the answer works.
ANTIFREEZE includes the adjacent identical vowels EE near the end of its written form.
BAZAAR contains AA as a pair of matching adjacent vowels in the middle of the spelling.
SKIING retains two adjacent I letters where the base word SKI meets the suffix -ING.
VACUUM contains the adjacent identical vowel pair UU in the middle of the word.
Why this group was difficult
- The words have unrelated everyday meanings
A coolant, market, activity and low-matter space offer no useful semantic category, so meaning-first sorting can stall. - SKIING can look visually unfamiliar
The legitimate II sequence occurs across the base word and suffix, making it easy to skim past when reading quickly. - The pattern uses different vowels
The entries do not repeat one common pair; they provide AA, EE, II and UU across four separate spellings.
How to spot this pattern next time
If four remaining words seem unrelated in meaning, inspect their exact spellings for repeated letters, shared positions or unusual letter boundaries.
Scan vowels independently of pronunciation. A written pattern such as the II in SKIING can be decisive even when speech does not emphasize two separate sounds.
Four useful facts behind the group
- ANTIFREEZE supplies EE as its adjacent matching vowel pair.
- BAZAAR supplies AA as its adjacent matching vowel pair.
- SKIING supplies II across the stem-and-suffix boundary.
- VACUUM supplies UU as its adjacent matching vowel pair.
Questions players ask
The details people search after seeing the group
What connects ANTIFREEZE, BAZAAR, SKIING and VACUUM?
Each word contains DOUBLE VOWELS: EE in ANTIFREEZE, AA in BAZAAR, II in SKIING and UU in VACUUM.
Where are the double vowels in SKIING?
They are the two adjacent I letters created in the spelling SKI plus ING, producing the sequence SKIING.
Does DOUBLE VOWELS mean any two vowels together?
On this board, it means two identical adjacent vowels, not merely two neighboring vowels of different kinds.
Why is pronunciation not enough to solve this group?
The rule concerns visible spelling, so inspecting the printed letters is more reliable than listening for separate vowel sounds.