some (not all) are:
veins, vein, sieve, sin, sine, seen, vine, vines, evens, even, eve, vie, eves, vies, in, is, seven, see, envies
inertia
One word you can make with the letters I N S A T I A B L E is "antibasil."
Pennie? pen? those are all i can think of if you don't have to use all of the letters
Tenancy
Vince
Enigma
The word inkiest can be made with those letters.
increasing
the word that can be form by rearranging these letters is "CHAMPAGNE"
Underwear !
signature
genitals