ACEFYNI

Make words with I

Missed: INEFFICACY (a pangram, darn it!)

Another pangram word exists

but is a bit obscure...

ACACIA AFFINE CAFFEINE CANINE CINE CYNIC EFFICACY EFFICIENCY FACIA FAIN FAINEANCY FANCIFY FIANCE FIANCEE FIEF FIFE FINANCE FINE IFFY INANE INEFFICIENCY INFANCY INNIE NAIF NIACIN NICE NIECE NINE NINNY

Pangrams: FAINEANCY