Hard girl with child going over Irish river (7)
I believe the answer is:
shannon
'irish river' is the definition.
(I've seen this before)
'hard girl with child going over' is the wordplay.
'hard' becomes 'h' (abbreviation used in pencil classifications).
'girl with' becomes 'ann' (I can't justify this - if you can you should give a lot more credence to this answer).
'child' becomes 'son' (male child).
'going over' means one lot of letters goes inside another.
'h'+'ann'='hann'
'hann' placed into 'son' is 'SHANNON'.
Can you help me to learn more?
(Other definitions for shannon that I've seen before include "Have some nosh, Nan, down by the river" , "Long-distance runner" , "current in Ireland" , "Ireland's longest river" , "Longest Irish river" .)