A clot is strangely indifferent to pain or pleasure (7)
I believe the answer is:
stoical
'indifferent to pain or pleasure' is the definition.
I can't tell whether this definition defines the answer.
'a clot is strangely' is the wordplay.
'strangely' is an anagram indicator.
'a'+'clot'+'is'='aclotis'
'aclotis' is an anagram of 'STOICAL'.
Can you help me to learn more?
(Other definitions for stoical that I've seen before include "able to endure suffering" , "Enduring hardship without complaining" , "Uncomplaining in the face of adversity" , "Showing endurance" , "Suffering patiently" .)