psychopathy

(dentistry) periodontitis

(pathology) collagenosis, collagen disease

(fiction) Hanahaki, an illness affecting those consumed by unrequited love that manifests as the coughing up of flowers, which clears up upon reciprocation. A fictional illness, it has found popularity among both Japanese and foreign online fanfic (especially) artists and authors for its poetic quality.

(literally) know the other side and yourself, a hundred battles will not be perilous

(idiomatic) Speak no ill-fated words; let no feeding cause you ailment; literally Diseases enter through the mouth, disasters come out of the mouth.