Small, shy, lazy person (4)
I believe the answer is:
slob
'lazy person' is the definition.
(I've seen this before)
'small shy' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'shy' becomes 'lob' (I've seen this in other clues).
's'+'lob'='SLOB'
(Other definitions for slob that I've seen before include "Untidy and lazy person" , "Slovenly layabout" , "Boor" , "Sort of ice" , "Fat, idle person" .)