ruffian vs tough guy

ruffian and tough guy both are nouns.

Word	Noun	Adjective	Verb	Adverb
ruffian	Yes	No	No	No
tough guy	Yes	No	No	No

As nouns, tough guy is a hyponym of ruffian; that is, tough guy is a word with a more specific, narrower meaning than ruffian:

Other hyponyms of ruffian include bullyboy, muscle, muscleman, skin, skinhead, plug-ugly.

ruffian (noun)	tough guy (noun)
a cruel and brutal fellow	someone who bullies weaker people