undeclare

As an adjective undeclared

is not declared.

As a verb undeclare is

to reverse the process of declaring; to unsay.

As verbs the difference between namespace and undeclare

is that namespace is (computing) to categorize by placing into a namespace while undeclare is to reverse the process of declaring; to unsay.

As a noun namespace

is (computing) a conceptual space that groups classes, identifiers, etc to avoid conflicts with items in unrelated code that have the same names.

As a noun variable

is variable.

As a verb undeclare is

to reverse the process of declaring; to unsay.

As a noun declaration

is declaration (written or oral indication of a fact, opinion, or belief).

As a verb undeclare is

to reverse the process of declaring; to unsay.

In transitive terms the difference between revoke and undeclare

is that revoke is to cancel or invalidate by withdrawing or reversing while undeclare is to reverse the process of declaring; to unsay.

As a noun revoke

is the act of revoking in a game of cards.

As verbs the difference between unsay and undeclare

is that unsay is to withdraw, retract (something said) while undeclare is to reverse the process of declaring; to unsay.