A primitive root; to shine, i.e. (by analogy) be (causatively, make) oily or gross -- become (make, wax) fat.
Englishman's Concordance
1) to be or become fat, grow fat 1a) (Qal) fat (substantive) 1b) (Hiphil) to make fat, show fatness Part of Speech: verb A Related Word by BDB/Strong’s Number: a primitive root Same Word by TWOT Number: 2410
Brown-Driver-Briggs
I. [שָׁמֵן] verbgrow fat (Late Hebrew Hiph`il id., also שֶׁמֶן Arabic be fat; Aramaic especially derived species and derivatives; שְׁמֵין adjective fat: Assyrian šammu, fat; Phoenician (Punic) שמןoil, so Palmyrene שמנא Lzb378; on relation of meanings Frä147); —
QalPerfect2masculine singular שָׁמַ֫נְתָּDeuteronomy 32:15 and Imperfect3masculine singular וַיִשְׁמַןDeuteronomy 32:15 both of Israel (prosperous and arrogant) under figure of fat beast; so Perfect3plural שָֽׁמְנוּJeremiah 5:28 (of wicked).
Deuteronomy 32:15 HEB: וַיִּשְׁמַ֤ן יְשֻׁרוּן֙ וַיִּבְעָ֔ט NAS: But Jeshurun grew fat and kicked-- KJV: But Jeshurun waxed fat, and kicked: INT:grew Jeshurun and kicked
Deuteronomy 32:15 HEB:יְשֻׁרוּן֙ וַיִּבְעָ֔ט שָׁמַ֖נְתָּ עָבִ֣יתָ כָּשִׂ֑יתָ NAS: grew fat and kicked-- KJV: and kicked: thou art waxen fat, thou art grown thick, INT: Jeshurun and kicked fat thick and sleek
Nehemiah 9:25 HEB:וַיֹּאכְל֤וּ וַֽיִּשְׂבְּעוּ֙ וַיַּשְׁמִ֔ינוּ וַיִּֽתְעַדְּנ֖וּ בְּטוּבְךָ֥ NAS: were filled and grew fat, And reveled KJV: and were filled, and became fat, and delighted INT: ate were filled and grew and reveled thing
Isaiah 6:10 HEB: הַשְׁמֵן֙ לֵב־ הָעָ֣ם NAS:Render the hearts of this KJV: of this people fat, and make their ears INT:Render the hearts people
Jeremiah 5:28 HEB: שָׁמְנ֣וּ עָשְׁת֗וּ גַּ֚ם NAS:They are fat, they are sleek, KJV:They are waxen fat, they shine: INT:are fat are sleek also