In obsolete|lang=en terms the difference between mockery and prank
is that
mockery is (obsolete) something insultingly imitative; an offensively futile action, gesture etc while
prank is (obsolete) full of gambols or tricks.
As nouns the difference between mockery and prank
is that
mockery is the action of mocking; ridicule, derision while
prank is (obsolete) an evil deed; a malicious trick, an act of cruel deception.
As a verb prank is
to adorn in a showy manner; to dress or equip ostentatiously.
As an adjective prank is
(obsolete) full of gambols or tricks.