The affix ghañ comes after the verb grah 'to seize' when in composition with preposition sam when the sense of the root refers to fist.,
The word मुष्टि means 'boxing', 'fist'; as, अहो मल्लस्य सङ्ग्राहः 'O! the clenching of the fist of the athlete'; अहो मुष्ठिकस्य सङ्ग्राहः 'O! the seizing of the boxer', meaning grasping firmly.
Why do we say 'referring to fist'? Observe सङ्ग्रहो धान्यस्य 'a collection of grain'.,