Glen holds two books and toy (6)
I believe the answer is:
dabble
'toy' is the definition.
(I've seen this before)
'glen holds two books' is the wordplay.
'two books' can mean two substitutions for 'book'.
'glen' becomes 'dale' (I've seen this in another clue).
'holds' means one lot of letters goes inside another.
'book' becomes 'b' (abbreviation for book).
'book' becomes 'b' (abbreviation for book).
'b'+'b'='bb'
'dale' enclosing 'bb' is 'DABBLE'.
'and' acts as a link.
(Other definitions for dabble that I've seen before include "Treat superficially" , "Splash or engage superficially in (6)" , "Take desultory interest" , "Take cursory interest (in)" , "Work with in an amateurish manner" .)