### Clue: Impassive as bone is set in concrete (6)
### Answer: STOLID 
 ### Explanation: Definition: Impassive
  T(as in T-bone, a large steak with a bone shaped like a "T" running through it – as an aside, a contemporary meaning of T-bone is a vehicle crash where the wreckage is shaped like a "T", one of the more lethal types of crashes)*** contained in***(is set in) SOLID(hard and firm,concrete)