One who compromises; especially, one who compromises readily(noun)
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Use "compromiser" in a sentence
"Rod Blagojevich, Quinn is known as a compromiser who often tries to please people with mixed results."
"Although he generally voted with his party on national issues, Mr. Stevens was known as a compromiser who was willing to work with Democrats and occasionally broke with Republicans on key issues."
"Clinton is known as a compromiser who basically wants to please."