• nen's room,
• ken's room,
• jen's room,
• mwn's room,
• msn's room,
• mdn's room,
• mrn's room,
• m4n's room,
• m3n's room,
• meb's room,
• mem's room,
• mej's room,
• meh's room,
• men'a room,
• men'z room,
• men'x room,
• men'd room,
• men'e room,
• men'w room,
• men's eoom

The adjective form of "men's room" is "men's". Example: "He entered the men's restroom".