straw man vs specious argument

straw man and specious argument both are nouns.

Word	Noun	Adjective	Verb	Adverb
straw man	Yes	No	No	No
specious argument	Yes	No	No	No

As nouns, specious argument is a hypernym of straw man; that is, specious argument is a word with a broader meaning than straw man:

straw man: a weak or sham argument set up to be easily refuted
specious argument: an argument that appears good at first view but is really fallacious

straw man (noun)	specious argument (noun)
an effigy in the shape of a man to frighten birds away from seeds	an argument that appears good at first view but is really fallacious
a weak or sham argument set up to be easily refuted
a person used as a cover for some questionable activity