Make a physical effort to pick up Hazel, say, around ten (5)
I believe the answer is:
exert
'make a physical effort to pick' is the definition.
I can't tell whether this definition defines the answer.
'up hazel say around ten' is the wordplay.
'up' says the letters should be written backwards (in down clue: letters go upwards).
'hazel say' becomes 'tree' (hazel is a kind of tree).
'around' indicates putting letters inside.
'ten' becomes 'X' (Roman numeral).
'tree' placed around 'x' is 'trexe'.
'trexe' written backwards gives 'EXERT'.
Can you help me to learn more?
(Other definitions for exert that I've seen before include "Work very hard" , "Strive" , "Bring quality or influence into play" , "Make a great effort" , "Bring into use, say strength" .)