Agaric and Death cup

Agaric noun - A saprophytic fungus of the order Agaricales having an umbrellalike cap with gills on the underside.

Death cup and agaric are semantically related. In some cases you can replace phrase "Death cup" with "Agaric", this terms are similar.

Death cup noun - Extremely poisonous usually white fungus with a prominent cup-shaped base; differs from edible Agaricus only in its white gills.

Agaric and death cup are semantically related. You can use "Agaric" instead a noun phrase "Death cup".