Entry 1 sense Webster, 1913 Quagmire /kwăg'-mīˌ-ẽr/ · Quag·mire · IPA /ˈkwæɡ.maɪɹ/ 01 n. Soft, wet, miry land, which shakes or yields under the feet. 1. Soft, wet, miry land, which shakes or yields under the feet. Syn. Morass; marsh; bog; swamp; fen; slough.