authorisation vs say-so

authorisation and say-so both are nouns.

Word	Noun	Adjective	Verb	Adverb
authorisation	Yes	No	No	No
say-so	Yes	No	No	No

As nouns, authorisation and say-so are synonyms defined as:

authorisation and say-so: the power or right to give orders or make decisions

Other synonyms of authorisation include authority, authorization, dominance, potency.

authorisation (noun)	say-so (noun)
the act of conferring legality or sanction or formal warrant	the power or right to give orders or make decisions
the power or right to give orders or make decisions	an authoritative declaration
official permission or approval	one chap's arbitrary assertion
a document giving an official instruction or command