Dowdy char, possibly, possessing strange power (8)
I believe the answer is:
frumpish
'dowdy' is the definition.
(synonyms)
'char possibly possessing strange power' is the wordplay.
'char possibly' becomes 'fish' (char is a kind of fish).
'possessing' indicates putting letters inside.
'strange' becomes 'rum' (similar in meaning).
'power' becomes 'p' (symbol in physics).
'rum'+'p'='rump'
'fish' placed around 'rump' is 'FRUMPISH'.
(Other definitions for frumpish that I've seen before include "unattractive" , "Dowdy" .)