Illegitimate

01 a. Not according to law; not regular or authorized; unlawful; improper.

1.
Not according to law; not regular or authorized; unlawful; improper.
2.
Unlawfully begotten; born out of wedlock; bastard; as, an illegitimate child.
3.
Not legitimately deduced or inferred; illogical; as, an illegitimate inference.
4.
Not authorized by good usage; not genuine; spurious; as, an illegitimate word.

Phrases & compounds

Illegitimate fertilization — the fertilization of pistils by stamens not of their own length, in heterogonously dimorphic and trimorphic flowers.

02 v. t. To render illegitimate; to declare or prove to be born out of wedlock; to bastardize; to illegitimatize.

imp. & p. p. Illegitimated; p. pr. & vb. n. Illegitimating

1.
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.