If the s here indicates a plural, then rails are wading birds that have a 5-letter name ending in s. (The word rail is obviously a 4-letter word.)
Eagles
star
Star Wars, Apollo 13, Titanic and Big are movie titles. They begin with the letters s, a, t and b.
Brats
5 points on a star
Unique letters: 5 (L,E,T,R,S) Total letters: 7 (L,E,T,T,E,R,S)
swami
scope ?
Points on a Star?
5 letters
stole