Anovulant and Preventative

Anovulant noun - A contraceptive in the form of a pill containing estrogen and progestin to inhibit ovulation and so prevent conception.

Preventative and anovulant are semantically related. In some cases you can use "Preventative" instead a noun "Anovulant".

Preventative noun - Any obstruction that impedes or is burdensome.

Anovulant and preventative are semantically related. Sometimes you can replace term "Anovulant" with "Preventative", this nouns are similar.