Previous solution:

How many words of three or more letters, including plurals, can you make from the five letters, using each letter only once? No words beginning with a capital are allowed. There’s at least one five-letter word.

Good 8 Very Good 12 Excellent 14

cero, ceros, cor, core, cores, corse, cos, ers, ore, ores, ors, rec, recs, res, roc, rocs, roe, roes, rose, score, sec, sore