Disperse a shaky cast having an unsuccessful winter (7)
I believe the answer is:
scatter
'disperse' is the definition.
(I know that disperse can be written as scatter)
'a shaky cast having an unsuccessful winter' is the wordplay.
'a shaky' is an anagram indicator.
'having' means one lot of letters go next to another.
'an unsuccessful winter' becomes 'ter' (I can't explain this - if you can you should give a lot more credence to this answer).
'cast' is an anagram of 'scat'.
'scat'+'ter'='SCATTER'
Can you help me to learn more?
(Other definitions for scatter that I've seen before include "Dissipate" , "Throw in various directions" , "Strew randomly" , "Throw in random directions" , "Sprinkle" .)