near-synonym       
noun [ C ]  language specialized (also near synonym) uk/ˌnɪə ˈsɪn.ə.nɪm/ us/ˌnɪr ˈsɪn.ə.nɪm/
 近义词
a word that has almost the same meaning as another word
  The words "hungry" and "peckish" are near-synonyms. “hungry”和“peckish”是近义词。 
 Near synonyms are more common than perfect synonyms. 近义词比完全同义词更常见。 
 - More examples
 - Near-synonyms may be regarded as equivalent for some purposes, but not others.
 - Thesauruses have tended to be simply lists of synonyms or near synonyms.
 - A description of the subjective feelings of happiness has a tendency to lose itself in the naming of near synonyms like contentment, peace of mind, etc.