You can use "cognitively impaired" as a more neutral and factual descriptor than either (and "cognitive impairment" as the generic term). It's also more broadly applicable. (I.e. If you got whacked in the head once too many while playing rugby, that might not count as "intellectual disability" according to some since it's not developmental. But it might interfere with learning math, so it's pretty indistinguishable in a practical sense!)