The initial idioms of the letter A

growth experience	a guiding light
a guilt trip	a guilty conscience needs no accuser
a guinea pig	a gut feeling
gut instinct	a gut reaction
gut-bucket	a gut-bucket
a hair in the butter	a hair out of place
a hair shirt	a hair's breadth
six in one, (and) half a dozen in the other	a halfway house
a half-wit	a hand in
hand-me-down	a hand with
a handful	a handle on
a hand-me-down	a hanger-on
a hang-up	a happy accident
a happy hunting ground	a happy medium
a hard egg to crack	a hard nut