Seamen gathered round seafront in a group? (2,5)
I believe the answer is:
en masse
'in a group?' is the definition.
(I've seen this before)
'seamen gathered round seafront' is the wordplay.
'gathered' indicates an anagram (the letters are gathered into a new order).
'round' indicates putting letters inside.
'seafront' becomes 's' (this might be a standard abbreviation I've not previously seen).
'seamen' with letters rearranged gives 'enmase'.
'enmase' going around 's' is 'EN MASSE'.
Can you help me to learn more?
(Other definitions for en masse that I've seen before include "All together as a group" , "Sees man (anag.)" , "As a body (Fr.)" , "All together - in France (2.5)" , "Many as one" .)