Bit of information given by trade union in current stoppage? (5)
I believe the answer is:
datum
'bit of information' is the definition.
(I've seen this in another clue)
'trade union in current stoppage?' is the wordplay.
'trade union' becomes 'TU' (abbreviation for trade union).
'in' indicates putting letters inside.
'current stoppage?' becomes 'dam' (I can't explain this - if you can you should believe this answer much more).
'tu' inserted within 'dam' is 'DATUM'.
'given by' acts as a link.
(Other definitions for datum that I've seen before include "Unit of dope" , "Something given" , "given to the Romans" , "Given item" , "bit of info" .)