Infirmative
Bouvier's Law Dictionary and Concise Encyclopedia · John Bouvier; revised by Francis Rawle · 1914
Bouvier's Law Dictionary and Concise Encyclopedia
Weakening.
Webster, Diet Tending to weaken or render Infirm; disprobabiiizing.
8 Benth. Jud. Ev. 13, 14.
Exculpatory is used by some authors as synonymous.
See Wills, Circ. Ev. 120; Best Pres. 8 217.