Homophones for astray, estray 

astray / estray [əˈstreɪ]

astray – predic. adj. & adv. – 1. in or into error or sin; 2. out of the right way

estray – adj., n., & v. – adj. – having gone into error; n. – 1. Law, a valuable animal found wandering away from its home; 2. a stray; 3. anything that has wandered away from its usual or normal plac

Discussion

This is an interesting example the old usage of ‘a’ and ‘e’ as prefixes. This had been a common practice centuries ago but has fallen out of fashion and many terms have dropped the prefix completely. These have survived.

Although very similar they are not interchangeable.

To keep from confusing them, note that the first is never a noun or verb while the second is never an adverb. If you remember their functions in a given sentence, the choice should be more obvious.

Quotes

astray

A Russian cruise missile has gone astray after a test launch, landing near a village in the north-western part of the country but inflicting no casualties.

~Russian cruise missile lands near village…(2015) – no author given – Belfast Telegraph

estray

An animal cannot be an estray when on the range where it was raised, and permitted by its owner to run, and especially when the owner is known to the party who takes it up.

~About the beastly problem…(2015) – Judy G. Russell