All 3 Uses

discredit
in
Pride and Prejudice
(Auto-generated)

She wished to discredit it entirely, repeatedly exclaiming, "This must be false!†
p. 198.9

discredit = damage the reputation of
I am glad it occurred to me to mention it; for it would really be discreditable to you to let them go alone.†
p. 206.1 *

discreditable = tending to damage the reputation of

standard suffix: The suffix "-able" means able to be. This is the same pattern you see in words like breakable, understandable, and comfortable.
You could scarcely escape discredit and misery.†
p. 356.5

discredit = damage the reputation of

Definitions:

(1) (discredit)
damage the reputation of -- often causing distrust of or disbelief in
(2) (meaning too rare to warrant focus)