fornication

UK: /ˌfɔː^rnɪˈkeɪʃ^ən/ US: /ˌfɔrnɪˈkeɪʃən/ ,(fôr′ni kā′shən)

WordReference Random House Unabridged Dictionary of American English © 2026

for•ni•ca•tion  (fôr′ni kā′shən), n. 

1. Medicine voluntary sexual intercourse between two unmarried persons or two persons not married to each other.
2. Theology, Bible [Bible.] idolatry.

• Late Latin fornicātiōn- (stem of fornicātiō). See fornicate¹, -ion
• 1300–50; Middle English fornicacioun

for•ni•ca•to•ry  (fôr′ni kə tôr′ē, -tōr′ē), adj. 

Collins Concise English Dictionary © HarperCollins Publishers::

fornication / ˌfɔːnɪˈkeɪʃən/ noun

1. voluntary sexual intercourse outside marriage
2. sexual immorality in general, esp adultery

WordReference Random House Learner's Dictionary of American English © 2026

for•ni•cate¹ /ˈfɔrnɪˌkeɪt/   v. [no object] , -cat•ed, -cat•ing. 

1. (of two persons not married to each other) to have voluntary sexual intercourse.

for•ni•ca•tion /ˌfɔrnɪˈkeɪʃən/  n. [uncountable]

WordReference Random House Unabridged Dictionary of American English © 2026

for•ni•cate¹  (fôr′ni kāt′), v.i., -cat•ed, -cat•ing. 

1. to commit fornication.

• Late Latin fornicātus (past participle of fornicārī to consort with prostitutes), equivalent. to Latin fornic- (stem of fornix) arch, vault, basement, brothel + -ātus -ate¹
• 1545–55

for′ni•ca′tor, n. 

for•ni•cate²  (fôr′ni kit, -kāt′), adj. [Biol.]

1. Biology arched or vaulted in form.

Also, for′ni•cat′ed. 

• Latin fornicātus, equivalent. to fornic- (see fornicate¹) + -ātus -ate¹
• 1820–30