substitute
noun
sub·sti·tute
| \ ˈsəb-stə-ˌtüt
, -ˌtyüt\
, -ˌtyüt\
Definition of substitute
(Entry 1 of 2)
: a person or thing that takes the place or function of another
substitute
verb
substituted;
substituting
Definition of substitute (Entry 2 of 2)
1a
: to put or use in the place of another
b
: to introduce (an atom or group) as a substituent
also
: to alter (something, such as a compound) by introduction of a substituent
a substituted benzene ring
2
: to take the place of : replace
: to serve as a substitute