Thinned glue will break (4)

I believe the answer is:

lull

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'break' is the definition.
(I know that lull is a type of break)

'thinned glue will' is the wordplay.
'thinned glue' becomes 'lu' (I can't justify this - if you can you should give a lot more credence to this answer).
'will' becomes ''ll' (contracted form, as in 'he'll' - 'he will').
'lu'+'ll'='LULL'

Can you help me to learn more?

(Other definitions for lull that I've seen before include "Calm - calm by deception" , "A temporary pause as in storm" , "Soothe or send to sleep" , "A pause or hiatus as in storm" , "Short period of calm" .)

I've seen this clue in The Independent.

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