What does the cryptic crossword clue "Tramp's in contact with relation (7)" mean?

The wordplay uses a charade (building blocks). STEPS (synonym="tramps") + ON (synonym="in contact with") = STEPSON The answer is STEPSON.

Tramp's in contact with relation (7)

Guardian Cryptic #28504 | 24 Across | 2021-07-22 flower