Agnate and Stepparent

Agnate noun - One related on the father's side.

Stepparent and agnate are semantically related In some cases you can use "Stepparent" instead a noun "Agnate".

Stepparent noun - The spouse of your parent by a subsequent marriage.

Agnate and stepparent are semantically related in relative topic. Sometimes you can use "Agnate" instead a noun "Stepparent", if it concerns topics such as member of a family.