barbecue vs cook out

barbecue is a noun but cook out is not a noun.

Word	Noun	Adjective	Verb	Adverb
barbecue	Yes	No	Yes	No
cook out	No	No	Yes	No

As verbs, barbecue and cook out are synonyms defined as:

Other synonyms of barbecue include barbeque.

barbecue (noun)	cook out (noun)
a rack to hold meat for cooking over hot charcoal usually out of doors
a cookout in which food is cooked over an open fire; especially a whole animal carcass roasted on a spit
meat that has been barbecued or grilled in a highly seasoned sauce

barbecue (verb)	cook out (verb)
cook outdoors on a barbecue grill	cook outdoors on a barbecue grill