override vs overrule

override is a noun but overrule is not a noun.

Word	Noun	Adjective	Verb	Adverb
override	Yes	No	Yes	No
overrule	No	No	Yes	No

As verbs, override and overrule are synonyms defined as:

Other synonyms of override include overthrow, overturn, reverse.

override (noun)	overrule (noun)
the act of nullifying; making null and void; counteracting or overriding the effect or force of something
a manually operated device to correct the operation of an automatic device

override (verb)	overrule (verb)
rule against	rule against
ride (a horse) too hard
counteract the normal operation of (an automatic gear shift in a vehicle)
prevail over