It might be your type

• Rarest type of bank deposit?
• Type least likely to turn up in a hospital
• Rare blood type
• Rarest of the main blood types in the U.S
• Uncommon blood type

Wiktionary Word definitions in Wiktionary
a. (context obsolete rare English): denying; renouncing; negative

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Abnegative \Ab"ne*ga*tive\, a. [L. abnegativus.] Denying; renouncing; negative. [R.] --Clarke.