A training habit we shed tears about (7)
I believe the answer is:
'a training habit' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps you can see a link between them that I can't see?
'we shed tears about' is the wordplay.
'shed' indicates anagramming the letters (shed can mean to spill or scatter).
'about' means one lot of letters goes inside another.
'tears' is an anagram of 'sater'.
'we' going within 'sater' is 'SWEATER'.
Can you help me to learn more?
(Other definitions for sweater that I've seen before include "Jersey may become" , "Top" , "Clobber" , "Heavy jersey" , "Wear" .)