asexual

Short definition from Wiktionary

Adjective

1. 1
   Nonsexual in nature, unmarked by sexual activity.
2. 2
   Not experiencing sexual attraction; lacking interest in or desire for sex.
3. 3
   Lacking distinct sex, lacking sexual organs.
4. 4
   Without sexual action; reproducing by some other method than sex.

Noun

1. 1
   A species which reproduces by asexual rather than sexual reproduction, or a member of such a species.
2. 2
   A person who does not experience sexual attraction; a person who lacks interest in or desire for sex.
3. 3
   Something which does not have a sex, or a word which refers to such a thing.