different between unwincing vs unwinning

English

un- +? wincing

unwincing (not comparable)

(chiefly figuratively) Not wincing, showing no sign of pain or discomfort.
- 1855, Elizabeth Gaskell, North and South, Chapter 41,^[1]
  So she sat almost motionless for hours in the drawing-room, going over the bitterness of every remembrance with an unwincing resolution.
- 1932, Barrett Willoughby, Spawn of the North, New York: Grosset & Dunlap, Chapter 8, 1,^[2]
  There the man sat, straight as a totem pole and as unwincing, while rain-squalls belabored his bare head and sweatered body.

un- +? winning

unwinning (comparative more unwinning, superlative most unwinning)

Not winning; unattractive.
- 1836, The Christian Examiner (volume 19, page 263)
  However, he quickly showed that he was an agent, and he made in the end a very indiscreet speech, in a most unwinning style.

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