How does the notion of “in defiance of” signify “notwithstanding”?

The semantic notion of “in defiance of” feels unrelated to “notwithstanding”! What underlies or relates these notions?

This question appertains to all languages that founds this conjunction on the Latin despectus e.g. French en dépit de, Italian a dispetto di, Spanish a despecho de, and Portuguese a despeito de. Don’t hesitate to edit this post to add to this list.

spite [13]

Spite was adapted from Old French despit ‘scorn, ill will’, which was also borrowed intact as despite [13]. This came from Latin dēspectus, the past participle of dēspicere ‘look down on’ (source of English despise [13]), which was a compound verb formed from the prefix dē- ‘down’ and specere ‘look’ (source of English spectacle, spy, etc). The use of in spite of and despite for ‘notwithstanding’ goes back via an intermediate ‘in defiance of’ to an original ‘in contempt of’.

Word Origins (2005 2e) by John Ayto. p 473 Left column.