> So in one usage someone who is kinda dumb would still be intelligent, just less intelligent than others.

100 IQ = 50% of the population is smarter than this.

80 IQ = not sure what the percentage is, but >50% of the population is smarter than this.

If any of the tables here are to be believed:

https://en.wikipedia.org/wiki/IQ_classification#Historical_I...

then 80 IQ could mean 80% of the population is smarter.

I'll rephrase my "kinda dumb" to "dumb as rocks".