Nilesh is a common Indian male name.

The name is based on one of two deities

Deity

A deity is a recognized preternatural or supernatural immortal being, who may be thought of as holy, divine, or sacred, held in high regard, and respected by believers....

, Vishnu or Shiva, in Hinduism

Hinduism

Hinduism is the predominant and indigenous religious tradition of the Indian Subcontinent. Hinduism is known to its followers as , amongst many other expressions...

, depending on which of its two Hindi

Hindi

Standard Hindi, or more precisely Modern Standard Hindi, also known as Manak Hindi , High Hindi, Nagari Hindi, and Literary Hindi, is a standardized and sanskritized register of the Hindustani language derived from the Khariboli dialect of Delhi...

 pronunciations is used. 'Nilesh' means 'the Blue God', and is one of the alternate names for Vishnu

Vishnu

Vishnu is the Supreme god in the Vaishnavite tradition of Hinduism. Smarta followers of Adi Shankara, among others, venerate Vishnu as one of the five primary forms of God....

, "The Preserver." Later, the name was also used to refer to Shiva

Shiva

Shiva is a major Hindu deity, and is the destroyer god or transformer among the Trimurti, the Hindu Trinity of the primary aspects of the divine. God Shiva is a yogi who has notice of everything that happens in the world and is the main aspect of life. Yet one with great power lives a life of a...

, "The Destroyer of Evil." The name is a combination (sandhi

Sandhi

Sandhi is a cover term for a wide variety of phonological processes that occur at morpheme or word boundaries . Examples include the fusion of sounds across word boundaries and the alteration of sounds due to neighboring sounds or due to the grammatical function of adjacent words...

) of two words: Neel (Blue) and Ish (Lord or God). Ish or Esh is also a Sanskrit

Sanskrit

Sanskrit , is a historical Indo-Aryan language and the primary liturgical language of Hinduism, Jainism and Buddhism.Buddhism: besides Pali, see Buddhist Hybrid Sanskrit Today, it is listed as one of the 22 scheduled languages of India and is an official language of the state of Uttarakhand...

word for head. Hence, the name can also be interpreted as 'Blue Head,' which refers to Lord Vishnu.