press vs iron out

press is a noun but iron out is not a noun.

Word	Noun	Adjective	Verb	Adverb
press	Yes	No	Yes	No
iron out	No	No	Yes	No

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

Other hyponyms of press include iron, press, calender.

As verbs, press and iron out are synonyms defined as:

Other synonyms of press include iron.

press (noun)	iron out (noun)
the act of pressing; the exertion of pressure
a weightlift in which the barbell is lifted to shoulder height and then smoothly lifted overhead
any machine that exerts pressure to form or shape or cut materials or extract liquids or compress solids
a machine used for printing
a tall piece of furniture that provides storage space for clothes; has a door and rails or hooks for hanging clothes
clamp to prevent wooden rackets from warping when not in use
the print media responsible for gathering and publishing news in the form of newspapers or magazines
a dense crowd of people
the state of demanding notice or attention

press (verb)	iron out (verb)
force or impel in an indicated direction	settle or put right
ask for or request earnestly	press and smooth with a heated iron
lift weights
exert pressure or force to or upon
place between two surfaces and apply weight or pressure
squeeze or press together
press and smooth with a heated iron
make strenuous pushing movements during birth to expel the baby
press from a plastic
create by pressing
crowd closely
exert oneself continuously, vigorously, or obtrusively to gain an end or engage in a crusade for a certain cause or person; be an advocate for
be urgent
to be oppressive or burdensome