We know we have an outstanding for Arrow. Those could be [Spot, Ring, Sign, Crusader, Sail].
We know that Pathology needs to hit Arrow. Unless someone knows another defn of Pathology (yay for House MD) it is just like researching diseases.
Words for Pathology would be...
Microscope - obvious connection
Spot - Liver spot, to spot a symptom, etc.
Sign - a symptom
Ring - eh... I liked this the best earlier, but Idk how ring ties into pathology.
Crusader - I guess there could of been a disease during the crusades
OK there is that.
Microscope does not need to match Arrow. We were only missing one on Arrow. And there is no way we get this clue and not microscope.
The second word though (the Arrow word) absolutely yes has to hit both Pathology and Arrow.
Someone check my logic, but I think that leaves us at Microscope -> Spot/Sign.
Personally I think Microscope->Sign, but I am gonna go read the game really fast to check on that.