- Augustly
- Authorized person
- Autistic
- Auto index
- Auto-ignition
- Autobiography
- Autodidact
- Automation
- Autonomy
- Axle-tree
- Azolla
- Azure
- Agoraphobic
- Avoirdupois
- Amaranthus
- Antiquary
- Auctor
- A bad pill to swallow
- A bed of roses
- A bird in hand is worth two in the bush
- A bit much
- A blood relative
- A cardinal error
- A dead duck
- A dead luck
- A dear john letter
- A good thing
- A grain of paddy
- A hollow laugh
- A host in himself
- A jam session
- A kings ransom
- A lack all
- A laughing stock
- A lazy susan
- A little water
- A man of few words
- A man of mark
- A matter of fact
- A matter of life and death
- A measure of
- A milk-n-honey drink
- A narrow escape
- A nasty one
- A near death experience
- A needle in a haystack
- A penny for your thoughts
- A pep talk
- A plant with sweet-scented roots
- A plum job
- A pretty kettle of fish
- A pretty penny
- A quixotic project
- A variety of sida
- A safe pair of hands
- A sea of
- A shot in the arm
- A shot in the locker
- A signal achievement
- A sorry sight
- Abaddon
- Abandoned
- Abandoned woman
- Abandonment
- Abased
- Abashed
- Abba
- Abbreviation
- Abbreviator
- Aberrant
- Abnormally
- Abode assylum
- Abolishment
- Abolitionism
- Abolitionist
- Abominable snowman
- Abomination
- Aboriginal
- Abreaction
- Abortive
- Abounding in waves
- About-face
- About-turn
- Above
- Above ones head
- Above ones reach
- Absently
- Absolute
- Aqiqah
- Absorb in
- Absorbed
- Absorbent
- Absorbing
- Abstract art
- Abstractedness
- Accent
- Acceptableness
- Access mode
- Accessary
- Accession