1) Carnal knowledge 2) Coitus 3) Congress 4) Copulation 5) Intercourse 6) Relation 7) Sex act 8) Sex activity 9) Sexual activity 10) Sexual congress 11) Sexual intercourse 12) Sexual practice 13) Sexual relation Found on https://www.crosswordclues.com/clue/coition
Co·i'tion noun [ Latin coitio , from coire to come together; co- + ire to go.] A coming together; sexual intercourse; copulation. Grew. Found on http://www.encyclo.co.uk/webster/C/107