Fortitude under cane construction (9)
I believe the answer is:
endurance
'fortitude' is the definition.
(I've seen this before)
'under cane construction' is the wordplay.
'construction' indicates anagramming the letters (answer constructed from certain letters).
'under'+'cane'='undercane'
'undercane' is an anagram of 'ENDURANCE'.
(Other definitions for endurance that I've seen before include "Stoicism" , "Staying power" , "Showing ablity to last" , "Ability to withstand hardship for long periods" , "ability to survive" .)