WordNet sense 1 (lacking symmetry):

unsymmetrical

WordNet sense 2 (having one side lower or smaller or lighter than the other):

lopsided

WordNet sense 3 (characterized by asymmetry in the spatial arrangement or placement of parts or components):

asymmetric

WordNet sense 4 (irregular in shape or outline):

crooked, crooked

WordNet sense 5 (contrary to rule or accepted order or general practice):

irregular