Gee-gee in river runs, one complains (7)

I believe the answer is:

niggler

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'one complains' is the definition.
I can't tell whether this definition defines the answer.

'gee-gee in river runs' is the wordplay.
'gee' becomes 'g' (synonyms).
'gee' becomes 'g' (synonyms).
'in' means one lot of letters goes inside another.
'river' becomes 'nile' (Nile is an example).
'runs' becomes 'r' (cricket abbreviation).
'g'+'g'='gg'
'gg' inserted into 'nile' is 'niggle'.
'niggle'+'r'='NIGGLER'

Can you help me to learn more?

(Another definition for niggler that I've seen is " Nit-picker".)

I've seen this clue in The Sun.

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