Pack, pack sank awkwardly (8)
I believe the answer is:
knapsack
'pack' is the definition.
(I've seen this before)
'pack sank awkwardly' is the wordplay.
'awkwardly' is an anagram indicator.
'pack'+'sank'='packsank'
'packsank' with letters rearranged gives 'KNAPSACK'.
(Other definitions for knapsack that I've seen before include "Traveller's or soldier's bag" , "Hiker's bag" , "Bag carried on back or shoulder" , "Pack sank (anag.)" , "Hiking bag" .)