As for for As to. "As for me, I am well." Say, as to me.
At Auction for by Auction. "The goods were sold at auction."
At for By. "She was shocked at his conduct." This very common solecism is without excuse.
Attain for Accomplish. "By diligence we attain our purpose." A purpose is accomplished; success is attained.
Authoress. A needless word—as needless as "poetess."
Avocation for Vocation. A vocation is, literally, a calling; that is, a trade or profession. An avocation is something that calls one away from it. If I say that farming is some one's avocation I mean that he practises it, not regularly, but at odd times.
Avoid for Avert. "By displaying a light the skipper avoided a collision." To avoid is to shun; the skipper could have avoided a collision only by getting out of the way.
Avoirdupois for Weight. Mere slang.
Back of for Behind, At the Back of. "Back of law is force."
Backwards for Backward.