Suitcases seen as joke in toboggan (7)
I believe the answer is:
luggage
'suitcases' is the definition.
(I've seen this before)
'joke in toboggan' is the wordplay.
'joke' becomes 'gag' ('gag' can be a synonym of 'joke').
'in' indicates putting letters inside.
'toboggan' becomes 'luge' ('luge' can be a synonym of 'toboggan').
'gag' going within 'luge' is 'LUGGAGE'.
'seen as' is the link.
(Other definitions for luggage that I've seen before include "gear carried" , "Traps" , "Suitcases for journey" , "Travel bags" , "Cases etc for travel" .)