It's really not a posh word. And it certainly means more than just 'talking' to those on the other side, as someone said.
Difficult to define since it's a catch-all phrase for many people and you won't get even 3 different mediums to agree on one definition.
Some only understand 'visuals' of those passed over, others count premonitions falling under that (and those premonitions could be literally seeing them clairvoyantly or just 'knowing' them all of a sudden, predicting future events), some people seem to use the word 'clairvoyant' interchangeably with any form of mediumship- therefore it would be good to see what people mean.
:yes: