[1] : The Collaborative International Dictionary of English v.0.48

sober \so"ber\, v. t. imp.  p. p. sobered; p. pr.  vb. n.
   sobering.
   to make sober.
   1913 webster

         there shallow draughts intoxicate the brain,
         and drinking largely sobers us again.    --pope.
   1913 webster
see also:
sobered sobering 

[2] : WordNet (r) 2.0

sobering
     adj : tending to make sober or more serious; "the news had a
           sobering effect"

Sobering >> S Words
Sobering, definition of term: Sobering
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