In my days of being competent at Scrabble there were so many words that our Scrabble playing group knew as legitimate words yet we had no idea at all what they meant. Half of the two letter words were like that and anything else with unusual 'Q, J and Z combinations'.
I like using a word beyond my normal inner-dictionary that is the right one, in the right place. There is a feeling that 'yes! I used that word...!'. Such words could have been heard on Radio 4 and never really made it to the inner-dictionary, yet, one day, the need arises for that word and it fits perfectly. It is so nice when that happens.