From WordNet (r) 3.0 (2006) [wn]:
asymmetric
adj 1: characterized by asymmetry in the spatial arrangement or
placement of parts or components [syn: asymmetrical,
asymmetric] [ant: symmetric, symmetrical]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Asymmetric \As`ym*met"ric\, Asymmetrical \As`ym*met"ri*cal\, a.
[See Asymmetrous.]
1. Incommensurable. [Obs.]
[1913 Webster]
2. Not symmetrical; wanting proportion; esp., not bilaterally
symmetrical. --Huxley.
[1913 Webster]