Quagmire dates back to the 1600s in the boggy sense and had the second meaning by the 1700s. It was formed from the joining of two words – quag and mire. Quag meant bog or marsh, possibly because the ground quaked underfoot. 

Slang usage: A quagmire is a difficult, complicated, or unpleasant situation which is not easy to avoid or escape from.

The earliest known use of the noun quagmire is in the mid 1500s. OED's earliest evidence for quagmire is from 1566, in a translation by William Adlington. quagmire is apparently formed within English, by compounding. 

The Quagmire family name was found in the USA in 1880. In 1880 there was 1 Quagmire family living in Mississippi. 

The quagmire theory suggests that American leaders had unintentionally and mistakenly led the country into the Vietnam War. The theory is categorized as an "orthodox" interpretation of the Vietnam War. 

Synonyms:- Swamp, morass, bog, marsh, mire, quag, marshland, fen, slough, quicksand, moss, moor, bayou, entanglement, quandary, difficulty, dilemma. 

Just the facts:

Quagmire Definition & Meaning - Merriam-Webster