A newlywed taking in garments at first to shorten (7)
I believe the answer is:
abridge
'shorten' is the definition.
(synonyms)
'a newlywed taking in garments at first' is the wordplay.
'newlywed' becomes 'bride' (newlywed woman).
'taking in' means one lot of letters goes inside another.
'at first' says to take the initial letters.
The initial letter of 'garments' is 'g'.
'bride' placed around 'g' is 'bridge'.
'a'+'bridge'='ABRIDGE'
'to' acts as a link.
(Other definitions for abridge that I've seen before include "Abbreviate, contract" , "Abbreviate, shorten" , "Shorten written work" , "Shorten, a book say, without losing the sense" , "Edit down" .)