Many words are used indiscriminately as nouns, adjectives or verbs, without any change of form.
He's capable of great violence, but he doesn't act indiscriminately.
There can be little doubt that the earlier of these expeditions were from Denmark, though the term Northmen was originally applied indiscriminately to all these terrible visitants from the unknown north.
On both sides was civil war, urged as fiercely as that against the common enemy, in which the parties sought allies indiscriminately among Christians and Mahommedans.
He also read largely, though somewhat indiscriminately, in French literature, and appears to have been particularly struck with Pascal's Provincial Letters, which he tells us he reperused almost every year of his subsequent life with new pleasure, and which he particularly mentions as having been, along with Bleterie's Life of Julian and Giannone's History of Naples, a book which probably contributed in a special sense to form the historian of the Roman empire.