allelopathy
noun
al·le·lop·a·thy ə-ˈlē-lə-ˌpa-thē 
-ˈle-lə-;
also
ˌa-lə-ˈlä-pə-thē : the suppression of growth of one plant species by another due to the release of toxic substances
allelopathic
ə-ˌlē-lə-ˈpa-thik
adjective -ˌle-lə-
Word History
Etymology
borrowed from German Allelopathie, from allelo- allelo- + -pathie -pathy
First Known Use
1938, in the meaning defined above