A word ending with a sixth case-affix is compounded with a case-inflected word with which it is in construction and the compound is tat-puruṣa,
As राजः पुरुषो=राजपुरुषः 'the king's man' ब्राह्मणकम्बलः 'the Brahmana's blanket.'
Vart:-When a word takes the genitive case because of its connection with a word ending in a krit affix; that word may be compounded with such a krit word. Rule 2.3.65., states the conditions when a krit-formed word governs the genitive case. Thus इक्ष्मप्रवश्चनः 'a hatchet' (a fuel cutter), पलाशशातनः 'Palasadestroyer.'
Why do we say so? The very fact that a special rule has been made for the compounding of genitive cases governed by krit-nouns, shows that other words which take genitive case by some special rule, are not so compounded. Such as the genitive cases ordained by (II. 3. 38, 51, 52). In fact the genitive case ordained by any rule of Panini, other than 2.3.51, is a 'pratipadavidhana' genitive; and a word taking genitive case according to those rules, is incapable of composition; see vårtika under 2.2.10.,