Search Result for "reactivity": 
Wordnet 3.0

NOUN (2)

1. responsive to stimulation;
[syn: responsiveness, reactivity]

2. ready susceptibility to chemical change; 



WordNet (r) 3.0 (2006):

reactivity
    n 1: responsive to stimulation [syn: responsiveness,
         reactivity]
    2: ready susceptibility to chemical change