stalwartyoudaoicibaDictYouDict[stalwart 词源字典]
stalwart: [14] The ancestor of stalwart was Old English stǣlwierthe. The second half of this compound adjective denoted ‘worth, worthy’, but the precise significance of the first element is not clear. It represents Old English stǣl ‘place’, perhaps used here in the metaphorical sense ‘stead’, so that etymologically the word would mean ‘able to stand someone in good stead’.

But stǣl itself may have been a contraction of stathol ‘foundation’, so the underlying meaning of the compound could be ‘foundation-worthy’, hence ‘firmly fixed’ (an adjective statholfæst existed in Old English, meaning ‘firm, stable’). South of the border it became stalworth, which had virtually died out by the end of the 17th century. But the Scottish variant stalwart, first recorded in the late 14th century, survived, and was brought into the general language by Sir Walter Scott.
[stalwart etymology, stalwart origin, 英语词源]
stalwart (adj.)youdaoicibaDictYouDict
late 14c., "resolute, determined," Scottish variant of stalworth, from Old English stælwierðe "good, serviceable," probably a contracted compound of staðol "base, foundation, support; stability, security" (from Proto-Germanic *stathlaz, from PIE root *sta- "to stand, set down, make or be firm;" see stet) + wierðe "good, excellent, worthy" (see worth). Another theory traces the first element of stælwierðe to Old English stæl "place," from Proto-Germanic *stælaz.