task vs proposition

task and proposition both are nouns.

Word	Noun	Adjective	Verb	Adverb
task	Yes	No	Yes	No
proposition	Yes	No	Yes	No

As nouns, proposition is a hyponym of task; that is, proposition is a word with a more specific, narrower meaning than task:

task (noun)	proposition (noun)
a specific piece of work required to be done as a duty or for a specific fee	a task to be dealt with
any piece of work that is undertaken or attempted	(logic) a statement that affirms or denies something and is either true or false
	a proposal offered for acceptance or rejection
	the act of making a proposal
	an offer for a private bargain (especially a request for sexual favors)

task (verb)	proposition (verb)
use to the limit	suggest sex to
assign a task to