Related Clues:

• Lacking liveliness
• Like 14-Across
• Like neon and xenon
• Like neon and argon
• At a dead end, as a case
• Siberian
• Absence of heat
• Opposite of active
• Like xenon and helium
• Perfectly still
• Not hot
• Far from friendly
• Hardly welcoming
• Unable to react, as helium
• Like 103-Down