Wikipedia:
In finance, a contrarian is one who attempts to profit by investing in a manner that differs from the conventional wisdom, when the consensus opinion appears to be wrong.
Λεξικό Χρυσοβιτσιώτη (6η έκδοση):
[...] Επενδυτής που αγοράζει όταν όλοι οι άλλοι πωλούν, δηλ. ενεργεί αντίθετα...