fixed vs rigid

fixed and rigid both are adjectives.

Word	Noun	Adjective	Verb	Adverb
fixed	No	Yes	No	No
rigid	No	Yes	No	No

As adjectives, fixed and rigid are synonyms defined as:

Other synonyms of fixed include set.

fixed (adjective)	rigid (adjective)
securely placed or fastened or set	designating an airship or dirigible having a form maintained by a stiff unyielding frame or structure
(of a number) having a fixed and unchanging value	incapable of or resistant to bending
fixed and unmoving	incapable of compromise or flexibility
incapable of being changed or moved or undone; e.g. "frozen prices"	fixed and unmoving
	incapable of adapting or changing to meet circumstances