In Sanskrit grammar a tatpuruṣa compound is a dependent determinative compound, i.e. a compound XY meaning a type of Y which is related to X in a way corresponding to one of the grammatical cases of X.
There are many tatpuruṣas (one for each noun case, and a few others besides); in a tatpuruṣa, one component is related to another. For example, "boathouse" is a dative compound, a house for a boat. It would be called a caturthī-tatpuruṣa (caturthī refers to the fourth case — that is, the dative). The most frequent kind is the genitive tatpuruṣa. Examples are:-
- jaya-prepsu = "victory-desiring". (accusative)
- varṣa-bhogya = "year - going to be enjoyed" = "to be enjoyed for a year" (adjective). (accusative)
- deva-datta = "god-given" = "given by the gods". (instrumental)
- viṣṇu-bali = "Vishnu-offering" = "offering to Vishnu". (dative)
- svarga-patita = "heaven-fallen" = "fallen from heaven". (ablative)
- tat-puruṣa = "that-man" in the sense of "that person's man". (genitive)
- vyāghra-buddhi = "tiger-thought" = "thought of it being a tiger". (genitive)
- yajur-veda = "sacrifice-knowledge" = "the knowledge of sacrifice", and the name of part of the Vedas. (genitive)
- rudrākṣa = rudra-akṣa = "Rudra-eye" = "the eye of Rudra". (genitive)
- raja-putra = "king-son" = "son of a king". (genitive)
- gṛha-jata = "house-born" = "born in the house". (locative)
- pūrvāhṇa-kṛta = "morning-done" = "done in the morning". (locative)
The word "tatpuruṣa" is an example of the type: see in the list above.
- caturthī-tatpuruṣa = "which is dative and a tatpuruṣa". (nominative), but a nominative tatpuruṣa is classed as a karmadhāraya.
- W. D. Whitney, Sanskrit Grammar: Including both the Classical Language and the Older Dialects, 1889.