outline vs block out

outline is a noun but block out is not a noun.

Word	Noun	Adjective	Verb	Adverb
outline	Yes	No	Yes	No
block out	No	No	Yes	No

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

Other hyponyms of outline include sketch out.

outline (noun)	block out (noun)
a schematic or preliminary plan
a sketchy summary of the main points of an argument or theory
the line that appears to bound an object

outline (verb)	block out (verb)
describe roughly or briefly or give the main points or summary of	plan where and when songs should be inserted into a theatrical production, or plan a theatrical production in general
trace the shape of	indicate roughly
draw up an outline or sketch for something	shield from light
	prevent from entering