The Collaborative International Dictionary
Idiosyncratical
Idiosyncratic \Id`i*o*syn*crat"ic\, Idiosyncratical \Id`i*o*syn*crat"ic*al\, a. Of peculiar temper or disposition; belonging to one's peculiar and individual character.
Wiktionary
idiosyncratical
a. (alternative form of idiosyncratic English)