The story
From vare- (of unknown origin) + -nicline (“nicotinic cholinergic receptor agonist”).
Etymology from Wiktionary, CC BY-SA 4.0.
varenicline
Today it means: A drug taken orally in the form of its tartrate C₁₃H₁₃N₃·C₄H₆O₆ as an aid to stop smoking. It binds to nicotinic cell receptors to block the activity of nicotine while also acting as an agonist to reduce nicotine cravings and withdrawal symptoms. It is marketed under the trademark Chantix. Full definition →