Head leading staff is a thin person (8)
I believe the answer is:
beanpole
'a thin person' is the definition.
Both the definition and answer are singular nouns.
Perhaps you can see an association between them that I can't see?
'head leading staff' is the wordplay.
'head' becomes 'bean' (bean is a kind of head).
'leading' is a charade indicator (letters next to each other) (some letters go in front of others).
'staff' becomes 'pole' (both can mean a stick).
'bean'+'pole'='BEANPOLE'
'is' is the link.
Can you help me to learn more?
(Other definitions for beanpole that I've seen before include "No, be pale if as tall and thin as this" , "Tall thin person - where runners are found?" , "Tall thin man of leguminous origin" , "A tall thin person, informally and leguminously" , "Support for runner" .)