Related Clues:
- Immovable type
- Undemonstrative to the max
- Dispassionate person
- Winter formation
- Seneca, for one
- Unemotional thinker
- Devoid of emotion
- Hard to rattle
- Winter's eave hanger
- Showing little emotion
- Danger during a thaw
- Not easily flapped
- Betraying no emotion
- Giving nothing away, in a way
- Uncomplaining sort