specify vs spell out

specify and spell out both are verbs.

Word	Noun	Adjective	Verb	Adverb
specify	No	No	Yes	No
spell out	No	No	Yes	No

As verbs, spell out is a hyponym of specify; that is, spell out is a word with a more specific, narrower meaning than specify:

specify (verb)	spell out (verb)
design or destine	make explicit; specify in detail
define clearly	orally recite the letters of or give the spelling of
select something or someone for a specific purpose	spell fully and without abbreviating
be specific about
decide upon or fix definitely
specify as a condition or requirement in a contract or agreement; make an express demand or provision in an agreement
determine the essential quality of