The initial idioms of the letter A

amuck	amuk
amuse with	amuse (someone or something) with
amuse	an
an/(one's) ivory tower	an/(one's) old flame
an éminence grise	A for effort
an about-face	absent-minded professor
an accident waiting to happen	an ace in the hole
an Achilles' heel	an acid test
acquired taste	an act of faith
an act of God	an act of war
an Aladdin's cave	an amber gambler
an ambulance chaser	angle
apple a day	An apple a day keeps the doctor away
apple polisher	an arm and a leg
an army marches on its stomach	an article of faith