"disorder, lack of discipline," 1783, from in- (1) "not, opposite of" + discipline (n.). Perhaps modeled on French indiscipline (18c.). Indisciplined as a past-participle adjective is attested from c. 1400.
word-forming element meaning "not, opposite of, without" (also im-, il-, ir- by assimilation of -n- with following consonant, a tendency which began in later Latin), from Latin in- "not," cognate with Greek an-, Old English un-, all from PIE root *ne- "not."
In Old French and Middle English often en-, but most of these forms have not survived in Modern English, and the few that do (enemy, for instance) no longer are felt as negative. The rule of thumb in English has been to use in- with obviously Latin elements, un- with native or nativized ones.
c. 1200, "penitential chastisement; punishment for the sake of correction," from Old French descepline "discipline, physical punishment; teaching; suffering; martyrdom" (11c., Modern French discipline) and directly from Latin disciplina "instruction given, teaching, learning, knowledge," also "object of instruction, knowledge, science, military discipline," from discipulus "pupil, student, follower" (see disciple (n.)).
The Latin word is glossed in Old English by þeodscipe. The meaning "treatment that corrects or punishes" is from the notion of "order necessary for instruction."
Meaning "branch of instruction or education" is first recorded late 14c. Meaning "system of rules and regulations" is from mid-14c. Meaning "military training" is from late 15c., via the notion of "training to follow orders and act in accordance with rules;" that of "orderly conduct as a result of training" is from c. 1500. Sense of "system by which the practice of a church is regulated, laws which bind the subjects of a church in their conduct" is from 1570s.
<a href="https://www.etymonline.com/word/indiscipline">Etymology of indiscipline by etymonline</a>
Harper, D. (n.d.). Etymology of indiscipline. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/indiscipline