Eccentric cheerleader at the head of column (5)
I believe the answer is:
crank
'eccentric' is the definition.
(I know that crank is a type of eccentric)
'cheerleader at the head of column' is the wordplay.
'cheerleader' becomes 'rank' (I can't justify this - if you can you should believe this answer much more).
'at' says to put letters next to each other (I've seen this in other clues).
'the head of' indicates taking the first letters.
The first letter of 'column' is 'c'.
'rank' put after 'c' is 'CRANK'.
Can you help me to learn more?
(Other definitions for crank that I've seen before include "Person of eccentric habits" , "Turn a handle - weirdo" , "Wind (up) - oddball" , "Person with strange ideas, or machine part" , "Eccentric - starting handle" .)