IPA: /nɒnˈtɒnɪk/
KK: /nɑnˈtɑnɪk/
Referring to something that is not tonic, meaning it does not have a stimulating or invigorating effect.
The nontonic beverage was refreshing but lacked the energy boost of a caffeinated drink.
Nontonic → It is formed from "non-" (meaning not) and "tonic" (from Greek "tonikos", meaning relating to tension or tone). The word "nontonic" refers to something that does not have a toning or tension-inducing effect.
Think of 'non-' meaning not, and 'tonic' relating to tone or tension — so nontonic means something that does not have a toning effect.