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Webster 1913 Edition
Unsincere
Unˊsin-cere′
,Adj.
 Not sincere or pure; insincere. 
[Obs.] 
Dryden. 
– Unˊsin-cere′ness
, Noun.
 [Obs.]
 Webster 1828 Edition
Unsincere
UNSINCE'RE
, a.1.
  Not sincere; hypocritical.  [See Insincere.]2.
  Not genuine; adulterated.3.
  Not sound; not solid.[Obsolete in the two last significations, and for the first, insincere is generally used.]