26 across
Sentimental
short
message
made
even
shorter
(4)
Sentimental short message made even shorter (4)
hints
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0
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The definition is at the beginning of the clue.
How the clue works
See Sentimental there — that's your definition, TWEE meaning excessively dainty or soppy. Now think of a TWEET, a short message, and "made even shorter" just tells you to lop off its last letter, which leaves you with TWEE.