Pathognomonic
Pathognomonic , adjective
[Greek {not transcribed} skilled in judging of diseases; pa`qos a disease + {not transcribed} skilled: compare French pathognomonique. See Gnomic.]
(Medicine) Specially or decisively characteristic of a disease; indicating with certainty a disease; as, a pathognomonic symptom.
The true pathognomonic sign of love jealousy.