also: にっこう
noun
A rare, clinical or euphemistic term for sexual intercourse, formed from the kanji for 'flesh' and 'intercourse'. Not commonly used in everyday conversation; more standard terms are 性交 (せいこう) or セックス.
See also: 性交
「肉交」という言葉は、医学書や古い文献で見かけることがある。
The word 肉交 can be found in medical books or old documents.
Compound of 肉 (にく, 'flesh') and 交 (こう, 'intercourse, exchange'). The exact origin is uncertain; it may be a coined Sino-Japanese term used in medical or formal contexts.