Own special son coming in becomes nuisance (4)
I believe the answer is:
pest
'nuisance' is the definition.
(I know that nuisance can be written as pest)
'own special son coming in' is the wordplay.
'own special' becomes 'pet' (I've seen this in another clue. I am not sure about the 'own' bit.).
'son' becomes 's' (genealogical abbreviation for son).
'coming in' is an insertion indicator.
'pet' going around 's' is 'PEST'.
'becomes' is the link.
Can you help me to learn more?
(Other definitions for pest that I've seen before include "Disease with a high death rate" , "Annoying person" , "Menace" , "A nuisance - step on it" , "Annoying thing" .)