antiestrogenic

anti-oestrogenic

adjective Referring to an effect that suppresses or inhibits oestrogenic activity.
 
noun An agent that counters oestrogenic activity.

antiestrogenic

adjective Referring to an effect that suppresses or inhibits estrogenic activity noun A general term for an agent that counters estrogenic activity

an·ti·es·tro·gen·ic

(an'tē-es-trō-jen'ik) Counteracting or suppressing estrogenic activity.
Synonym(s): antioestrogenic.