| key out |
| keynote |
| lever(noun, control, cause, answer, switch) |
| linchpin |
| marker(noun, check, information, influence, report) |
| master(adjective, lead, head, boss, exemplary) |
| master key(expression, idiom, opening, instrumentality) |
| name(verb, important, essential, critical, basic) |
| padlock(noun, twist, handle, fastener, wad) |
| passport(noun, answer, country, solution, identification) |
| pattern(adjective, exemplary) |
| pitch(noun, edge, tone, tinge) |
| primordial(adjective, important, head, significant, beginning) |
| rudimentary(adjective, important, head, significant, beginning) |
| samara |
| set |
| special(adjective, important, core, chief, foremost) |
| star(adjective, lead, head, master, boss) |
| suggestion(noun, sign, prompt, hint, trace) |
| tip-off(noun, information, sign, influence, prompt) |