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Webster 1913 Edition
Shrilly
Shril′ly
,adv.
 In a shrill manner; acutely; with a sharp sound or voice. 
 Shril′ly
,Adj.
 Somewhat shrill. 
[Poetic] 
Sir W. Scott.
 Some kept up a 
shrilly 
mellow sound. Keats.
Webster 1828 Edition
Shrilly
SHRIL'LY
,adv.