A case-inflected word denoting the qualifier (the Adjective), is compounded diversely with a case-inflected word denoting the thing thereby qualified, (the Substantive), the latter being in agreement (same case) with the former and the resulting compound is tat-puruṣa ,
The 'discriminator' is called विशेषण and the 'discriminated' is called विशेष्य as नीलोत्पलं 'a blue lotus,' रक्तोत्पलं 'a red lotus.'
By using in the rule the expression बहुल ' diversely' it is meant that in some cases it is imperative to make a compound (नित्यसमास) as कृष्णसर्पः 'a black snake.' लोहितशालिः 'red rice':-and sometimes it is forbidden; as, रामो जामदग्न्यः 'Rama called also Jamadagnya' (as being the son of Jamadagni): अर्जुनः कार्त्तवीर्यः -and in some cases it is optional, नीलमुत्पलं or नीलोत्पलं.
Why do we say 'qualifier ?' Observe तक्षकः सर्पः 'the Takshaka snake.'
Why do we say 'qualified.' Observe लोहितस्तक्षकः 'the red Takshaka.',