pathologic (adj.)

"science of diseases," 1610s, from French pathologie (16c.), from medical Latin pathologia "study of disease," from Greek pathos "suffering" (from PIE root *kwent(h)- "to suffer") + -logia "study" (see -logy). In reference to the study of abnormal mental conditions from 1842. Ancient Greek pathologia was "study of the passions;" the Greek word for "science of diseases" was pathologike ("pathologics").

Middle English -ik, -ick, word-forming element making adjectives, "having to do with, having the nature of, being, made of, caused by, similar to," from French -ique and directly from Latin -icus or from cognate Greek -ikos "in the manner of; pertaining to." From PIE adjective suffix *-(i)ko, which also yielded Slavic -isku, adjectival suffix indicating origin, the source of the -sky (Russian -skii) in many surnames. In chemistry, indicating a higher valence than names in -ous (first in benzoic, 1791).

In Middle English and after often spelled -ick, -ike, -ique. Variant forms in -ick (critick, ethick) were common in early Modern English and survived in English dictionaries into early 19c. This spelling was supported by Johnson but opposed by Webster, who prevailed.

1680s, "pertaining to disease," formed in English from pathologic + -al (1). Sense of "worthy to be a subject of pathology, morbid, excessive" (as in pathological liar) is attested from 1845. Related: Pathologically.