love child

a child born out of wedlock.

Origin of love child

First recorded in 1795–1805

Then, at the end of the first trimester, John drops a bombshell: there is not one love-child, but two.

If The Peace Talks Were A Movie |Matthew Kalman |December 12, 2013 |DAILY BEAST
He was, what men (misusing the holiest of words) have named, a "love-child."

My Fire Opal, and Other Tales |Sarah Warner Brooks
Not Fernando his love-child, but Diego the elder, who was born in Lisbon.

1492 |Mary Johnston
Although it is the book by which Signor Papini is best known, it is not his love-child.

Idling in Italy |Joseph Collins

"He is handsome, indeed, because he is a love-child," said another.

The Folk-Tales of the Magyars |Various
Am'adis of Gaul, a love-child of king Per'ion and the princess Elize'na.

Character Sketches of Romance, Fiction and the Drama, Vol 1 |The Rev. E. Cobham Brewer, LL.D.

love child

euphemistic an illegitimate child; bastard