Source : Webster's Revised Unabridged Dictionary (1913)

Unsymmetrically \Un`sym*met"ric*al*ly\, adv.
   Not symmetrically.

Source : WordNet®

unsymmetrically
     adv : in an asymmetrical manner; "they were asymmetrically
           arranged" [syn: {asymmetrically}] [ant: {symmetrically}]