adj.
 relating to chemistry or chemicals. 
▸relating to or denoting the use of poison gas or other chemicals as weapons of war.
n.
 a distinct compound or substance, especially one which has been artificially prepared or purified. 
▸an addictive drug.
 
  Derivative
  
  Etymology
  C16: from Fr. chimique or mod. L. chimicus, chymicus, from med. L. alchymicus, from alchimia (see alchemy).