Shorten and give it a loose perm all round (7)
I believe the answer is:
curtail
'shorten' is the definition.
(I know that curtail is a more specific form of the action shorten)
'give it a loose perm all round' is the wordplay.
'give' means one lot of letters go next to another.
'loose' indicates an anagram (letters are loosened from their original positions).
'perm' becomes 'curl' (I am not sure about this - if you are sure you should believe this answer much more).
'all round' indicates putting letters inside.
'it'+'a' is 'ita'.
'ita' anagrammed gives 'tai'.
'tai' going inside 'curl' is 'CURTAIL'.
'and' is the link.
Can you help me to learn more?
(Other definitions for curtail that I've seen before include "Reduce in extent" , "Impose a restriction on" , "Cut short (an activity)" , "'Cut short, restrict (7)'" , "Cut short like canine appendage" .)