Meaning of UNALLOYED in English
[adjective] [literary] - (esp. of a positive feeling) not spoilt by any amount of negative feeling; pureSpending time with one's family is never an unalloyed pleasure (= There are bad things about it too).We had the perfect holiday - two weeks of unalloyed bliss.
Cambridge English vocab. Кембриджский английский словарь. 2012