What is "soothest"

Sooth \Sooth\ (s[=oo]th), a.; also adv. [Compar. Soother (s[=oo]th"[~e]r); superl. Soothest.] [OE. soth, AS. s[=o][eth], for san[eth]; akin to OS. s[=o][eth], OHG. sand, Icel. sannr, Sw. sann, Dan. sand, Skr. sat, sant, real, genuine, present, being; properly p. pr. from a root meaning, to be, Skr. as, L. esse; also akin to Goth. sunjis true, Gr. 'eteo`s, Skr. satya. [root]9. Cf. Absent, Am, Essence, Is, Soothe, Sutee.]

1. True; faithful; trustworthy. [Obs. or Scot.]

   The sentence [meaning] of it sooth is, out of doubt.
   --Chaucer.

   That shall I sooth (said he) to you declare.
   --Spensser.

2. Pleasing; delightful; sweet. [R.]

   The soothest shepherd that ever piped on plains.
   --Milton.

   With jellies soother than the creamy curd.
   --Keats.

a. (context archaic English) (en-superlative of: sooth)