The longest I can manage are four-letter words
alphabet
The biggest word you can make with the letters e, r, t, a, I, a, and a is "airrate." However, if you consider common usage, "airrate" may not be widely recognized. The most common word using those letters is "air," but "arteria" is also a valid term, referring to a type of blood vessel.
You cannot make any seven letter words from these letters. The biggest words that can be made have four letters. They are:AgeeAghaGheeOgee
The word you can make with the letters e, f, i, p, and r is "frie." Additionally, you can also form the word "fire."
face paint acquainted availed
Sized
The two letters in the word MAKE that have the same number of letters between them in the word as in the alphabet are A and E. In the word MAKE, the letter A is two letters away from M and E is also two letters away from K in the alphabet.
The word inkiest can be made with those letters.
One word you can make with the letters I N S A T I A B L E is "antibasil."
inertia
The words:adept, apted, baked, bated, bepat, pated, tapedare all the acceptable five-letter words that you can make from those letters.
Refuge