verb

present and explain (a theory or idea) in detail.

he was expounding a powerful argument

present,put forward,set forth,proffer,offer,advance,propose,propound,frame,give an account of,recount,explain,give an explanation of,detail,spell out,describe,discuss,explicate,delineate,elucidate,elaborate on,expand on,expatiate on,dwell on,harp on,discuss at length