The initial idioms of the letter A

in stitches	A stitch in time
a stitch in time (saves nine)	stitch in time, a
stock phrase	a stone cold fox
a stone's throw	a stone's throw away
stone's throw	a stool pigeon
a stopped clock is right twice a day	stop-watch critic
a storm in a teacup	a storm in a teakettle
a storm in a teapot	stovepipe hat
a straight arrow	a straight shooter
a straw in the wind	streak of good luck
a stroke of luck	a strong stomach
stud muffin	a stud-muffin
a stuffed shirt	a stumbling block
sugar pill	a safe bet
sure thing	shady character