The story
Transliteration of Hindi हिंदुत्व (hindutva) / Bengali হিন্দুত্ব (hindutto, literally “Hinduness”). Coined by Bankim Chandra Chatterjee in its literal sense, in his novel Anandamath, published in 1882. The term was popularised by Chatterjee's friend Chandranath Basu in his magnum opus titled "Hindutva : Hindur Prakrita Itihaas", published in 1892. It was later appropriated and popularised in its modern political sense by Vinayak Damodar Savarkar in his political pamphlet titled "Hindutva : Who is a Hindu?", published in 1923.
Etymology from Wiktionary, CC BY-SA 4.0.