- undertone - a quiet or hushed tone of voice; "spoke in undertones"
 --1 is a kind of tone, tone of voice
 
- undertone, undercurrent - subdued emotional quality underlying an utterance; implicit meaning
 --2 is a kind of meaning, substance
 
- undertone, tinge - a pale or subdued color
 --3 is a kind of shade, tint, tincture, tone
 
- undertone, undercurrent - subdued emotional quality underlying an utterance; implicit meaning