a (an) - not, without, greek words

anoxia

deprivation of (state of being without) oxygen

anhydrous

destitute of (without) water

anomoly

deviation from the common rule

anesthetic

drug that produces anesthesia

hypertrophy

enlargement of a body part

aseptic

free from disease-causing microorganisms

atheism

godlessness

anemia

lack of a normal number of red blood cells

atrophy

lack of growth from disuse or want of nourishment

anesthesia

loss of feeling or sensation resulting from ether, chloroform

anonymous

nameless; of unknown or unnamed origin

amoral

not moral; without a sense of moral responsibility

anomalous

not normal; abnormal

asymptomatic

showing no symptoms of disease

apnea

temporary cessation of breathing

anarchy

total absence of rule or government; confusion; disorder

atypical

unlike the typical

amorphous

without definite form or shape