Quiet and strong, showed indifference (8)
I believe the answer is:
shrugged
'showed indifference' is the definition.
(to shrug is to show indifference about something)
'quiet and strong' is the wordplay.
'quiet' becomes 'sh'.
'and' means one lot of letters go next to another.
'strong' becomes 'rugged' ('rugged' can be similar in meaning to 'strong').
'sh'+'rugged'='SHRUGGED'
(Other definitions for shrugged that I've seen before include "Hunched the shoulders, showing indifference say" , "Moved the shoulders disclaimingly" , "Raised one's shoulders to show indifference or resignation" , "Raised and lowered shoulders to show indifference" , "Raised and dropped shoulders to indicate indifference" .)