Bloom is the first to blubber at bereavement of leading Frenchman (7)
I believe the answer is:
blossom
'bloom' is the definition.
(I've seen this before)
'the first to blubber at bereavement of leading frenchman' is the wordplay.
'the first to' suggests taking the first letters.
'at' is a charade indicator (letters next to each other).
'bereavement' becomes 'loss' (I've seen this before).
'leading' says to take the initial letters.
'frenchman' becomes 'm' (abbreviation for Monsieur - like 'Mr').
The first letter of 'blubber' is 'b'.
The initial letter of 'of' is 'o'.
'b'+'loss'+'o'+'m'='BLOSSOM'
'is' is the link.
(Other definitions for blossom that I've seen before include "Flowers on a tree/bush" , "Flourish and prosper" , "better period results" , "Fruit tree flowers" , "Produce flowers" .)