Wise old Greek squad, running away (5)
I believe the answer is:
plato
'greek squad running away' is the definition.
I can't judge whether this defines the answer.
'wise old' is the wordplay.
'wise' becomes 'plat' (I can't explain this - if you can you should believe this answer much more).
'old' becomes 'o' (abbreviation).
'plat'+'o'='PLATO'
Can you help me to learn more?
(Other definitions for plato that I've seen before include "Moon crater named after Greek philosopher" , "Republican writer?" , "Republic author" , "A plot (anag) (known to Aristotle?)" , "Ancient Athenian philosopher, pupil of Socrates" .)