Illegitimate \Il`le*git"i*mate\, v. t. [imp. & p. p. {Illegitimated}; p. pr. & vb. n. {Illegitimating}.] To render illegitimate; to declare or prove to be born out of wedlock; to bastardize; to illegitimatize. The marriage should only be dissolved for the future, without illegitimating the issue. --Bp. Burnet.