undernote
/ˈʌndərnɒt/Definitions
1. noun
A faint sound or note that is perceived beneath a louder sound or note, or a subtle suggestion or implication.
“The undernote of tension in the atmosphere made the audience feel uneasy.”
2. verb
To add or suggest a subtle implication or meaning, often unintentionally.
“Her comment undernoted the complexity of the issue.”