overtone            
noun [ C ] uk/ˈəʊ.və.təʊn/ us/ˈoʊ.vɚ.toʊn/
 [ usually plural ]暗示;弦外之音,言外之意 
something that is suggested, but is not clearly stated
  The concert was supposed to be a charity event but it had strong political overtones. 这场音乐会原是为慈善事业筹款的,但却带有浓厚的政治色彩。 
 There was an overtone of regret in his farewell speech. 他的告别演说中流露出遗憾之意。 
  physics, music specialized泛音 
a frequency of a sound that is higher than the fundamental (= the lowest normal frequency)