WARNING, WAFFLE AHEAD....
I would readily differentiate between an intellectual and an intelligent being.
I would suspect that the average person would consider somebody to be intelligent if they displayed a degree of ability [with regard to one's thought processes]* that can be taken to be superior to the standard with which it is being judged [ie. my builder thinks my lawyer is intelligent, MENSA think he doesn't make the grade, and MENSA adore René Descartes].
Essentially, intelligence is relative- do you wish it to be defined in relation to society? or amongst us? or those upon a higher intellectual plane [one does exsist,scary as the thought may seem...
]? It depends whom is judging said intelligence.
* this condition would encompass one's ability to reason, solve problems, his/her creativity etc.