optional

As adjectives the difference between optional and discretional

is that optional is not compulsory; left to personal choice; elective while discretional is discretionary.

As an adjective optional

is not compulsory; left to personal choice; elective.

As a verb substitute is

to use in place of something else, with the same function.

As a noun substitute is

a replacement or stand-in for something that achieves a similar result or purpose.

As a noun exigency

is the demands or requirements of a situation (usually plural ).

As an adjective optional is

not compulsory; left to personal choice; elective.

As adjectives the difference between optional and random

is that optional is not compulsory; left to personal choice; elective while random is having unpredictable outcomes and, in the ideal case, all outcomes equally probable; resulting from such selection; lacking statistical correlation.

As a noun random is

a roving motion; course without definite direction; lack of rule or method; chance.

As an adjective optional

is not compulsory; left to personal choice; elective.