concoct vs dream up

concoct and dream up both are verbs.

Word	Noun	Adjective	Verb	Adverb
concoct	No	No	Yes	No
dream up	No	No	Yes	No

As verbs, concoct and dream up are synonyms defined as:

Other synonyms of concoct include hatch, think of, think up.

concoct (verb)	dream up (verb)
make a concoction (of) by mixing	devise or invent
devise or invent
prepare or cook by mixing ingredients
invent