Useless family invests pence for awkward rustic (7)
I believe the answer is:
bumpkin
'awkward rustic' is the definition.
'bumpkin' can be an answer for 'rustic' (bumpkin is a kind of rustic). I am unsure of the 'awkward' bit.
'useless family invests pence' is the wordplay.
'useless' becomes 'bum' (I've seen this in other clues).
'family' becomes 'kin' (synonyms).
'invests' indicates putting letters inside (inserted letters are invested).
'pence' becomes 'p'.
'bum'+'kin'='bumkin'
'bumkin' enclosing 'p' is 'BUMPKIN'.
'for' is the link.
Can you help me to learn more?
(Other definitions for bumpkin that I've seen before include "Simple rustic" , "Country person with awkward manners" , "Country cousin" , "Daft countryman" , "Clumsy rustic" .)