Undertone/ˈʌndərtəʊn/ Definition 1 of 3Pro Tip 1/3Subtle Emphasis Undertone can stress a subtle quality or feeling that's not obvious. Despite his smile, there was an undertone of sadness in his words. Pro Tip 2/3Implicit Meaning An undertone suggests something implied but not directly expressed. Her compliment came with an undertone of envy. Pro Tip 3/3Cultural Sensitivity Be attentive to cultural differences when detecting undertones. His joke carried an undertone that was misunderstood by the international audience.