Very entertaining European elders? (5)
I believe the answer is:
trees
'elders?' is the definition.
(elder is a kind of tree)
'very entertaining european' is the wordplay.
'very' becomes 'tres' (French).
'entertaining' means one lot of letters goes inside another.
'european' becomes 'e' (abbreviation e.g. EU).
'tres' placed around 'e' is 'TREES'.
(Other definitions for trees that I've seen before include "Elms, pines etc" , "Components of forest" , "''I see ... of green / Red roses too'' (What a Wonderful World)" , "Woods" , "Tall, perennial, woody plants" .)