The letters in EFFECTIVE make 41 words of two letters or more. The longest is EFFECTIVE at 9 letters, and the highest-scoring is EFFECTIVE at 20 points.
No other single word uses all 9 letters of EFFECTIVE. EFFECTIVE has 9 letters: 4 vowels and 5 consonants, worth 20 points before any board bonuses.
9-letter words 1
7-letter words 1
evictee12
6-letter words 2
effect14effete12
5-letter words 4
civet10evict10evite8fecit10
4-letter words 12
cete6cite6etic6feet7fete7fice9fief10fife10five10teff10tiff10vice9
3-letter words 16
cee5eff9eft6eve6fee6fet6fie6fit6ice5iff9tee3tic5tie3vee6vet6vie6
2-letter words 5
ef5et2if5it2ti2
Words are from our open word list and include some game-only words. Rude words are left out of this page; the unscrambler shows every valid word, lets you add blank tiles and filter by length.