Unkempt educationist left in threadbare clothing (10)
I believe the answer is:
bedraggled
'unkempt' is the definition.
(I've seen this before)
'educationist left in threadbare clothing' is the wordplay.
'educationist' becomes 'bed' (someone with a Bachelor of Education degree).
'left' becomes 'l' (common abbreviation).
'in' means one lot of letters goes inside another.
'threadbare clothing' becomes 'ragged' (ragged clothing).
'l' inserted within 'ragged' is 'raggled'.
'bed'+'raggled'='BEDRAGGLED'
(Other definitions for bedraggled that I've seen before include "muddy and dripping" , "Wet and dirty" , "Very untidy" , "Dishevelled" , "Unkempt" .)