From an unused root meaning to take off the shoes; unsandalled -- barefoot, being unshod.
Englishman's Concordance
1) barefoot 1a) bareness, being unshod (substantive) Part of Speech: adjective A Related Word by BDB/Strong’s Number: from an unused root meaning to take off the shoes Same Word by TWOT Number: 861a
Brown-Driver-Briggs
יָחֵףadjectivebarefoot, always absolute יָחֵףIsaiah 20:2 4t.; — הלך עָרוֺם וְיָחֵףIsaiah 20:2 (רַגְּלֶ֑ךָ נַעַלְךָ תַחֲלֹץ מֵעַל in preceding clause), Isaiah 20:3; הֹלֵךְ יָחֵף2 Samuel 15:30; נָהַג יָחֵףIsaiah 20:3; apparently=substantive, מִנְעִי רַגְלֵךְ מִיָּחֵףJeremiah 2:25withhold thy foot from bareness (Syriac discalceatio).
2 Samuel 15:30 HEB:וְה֖וּא הֹלֵ֣ךְ יָחֵ֑ף וְכָל־ הָעָ֣ם NAS: and he walked barefoot. Then all KJV: and he went barefoot: and all the people INT: and he walked barefoot all the people
Isaiah 20:2 HEB:הָלֹ֖ךְ עָר֥וֹם וְיָחֵֽף׃ ס NAS: going naked and barefoot. KJV: walking naked and barefoot. INT: going naked and barefoot
Isaiah 20:3 HEB:יְשַׁעְיָ֖הוּ עָר֣וֹם וְיָחֵ֑ף שָׁלֹ֤שׁ שָׁנִים֙ NAS: naked and barefoot three KJV: naked and barefoot three INT: Isaiah naked and barefoot three years
Isaiah 20:4 HEB:וּזְקֵנִ֖ים עָר֣וֹם וְיָחֵ֑ף וַחֲשׂוּפַ֥י שֵׁ֖ת NAS: naked and barefoot with buttocks KJV: naked and barefoot, even with [their] buttocks INT: and old naked and barefoot uncovered with buttocks
Jeremiah 2:25 HEB:מִנְעִ֤י רַגְלֵךְ֙ מִיָּחֵ֔ף [וּגֹורֹנֵךְ כ] NAS: your feet from being unshod And your throat KJV: thy foot from being unshod, and thy throat INT: Keep your feet unshod barn thirst
discalceatio).