From an unused root perhaps meaning to move softly; (as a noun) a necromancer (from their soft incantations), (as an adverb) gently -- charmer, gently, secret, softly.
Englishman's Concordance
1) gentleness, softness 1a) gently 1b) flowing 1c) softly 1d) enchanter, necromancer (substantive) Part of Speech: adverb A Related Word by BDB/Strong’s Number: from an unused root perhaps meaning to move softly Same Word by TWOT Number: 72b
Brown-Driver-Briggs
אַטsubstantivegentleness, used only adverbially: —
a.as adverb. accus. 1 Kings 21:27וַיְהַלֵח ַאט׃ and he (Ahab) went about softly (that is, in penitence);
b.withלְ of norm or state (as in לָבֶטַח, see לְ) 2 Samuel 18:5לְאַטלִֿי לַנַּעַר (deal) gently for me with the young man, Isaiah 8:6 the waters of Shiloah הַהֹלְכִים לְאַ֑ט that go Gently; with pretonic qameƒJob 15:11דָּבָר לָאַט עִמָּֽח׃ a word (spoken) gently with thee; with suffix Genesis 33:14 and I אֶתְנַהֲלָה לְאִטִּי will lead on gently (literally according to my Gentleness).
לְאַטלָאַטgently, see אַט below אטט above
לאך (√ of מַלְאָךְמְלָאכָה, compare Arabic , send, messenger, Ethiopic send a messenger, see be sent, wait on, minister; =Hebrew מַלְאָךְ; compare Phoenician מלאךmessenger; Late Hebrew מַלְאָךְ Aramaic מַלְאֲכָא, as in Hebrew)
Genesis 33:14 HEB:וַאֲנִ֞י אֶֽתְנָהֲלָ֣ה לְאִטִּ֗י לְרֶ֨גֶל הַמְּלָאכָ֤ה NAS: and I will proceed at my leisure, according to the pace KJV: and I will lead on softly, according as INT: and I will proceed my leisure to the pace of the cattle
2 Samuel 18:5 HEB:אִתַּי֙ לֵאמֹ֔ר לְאַט־ לִ֖י לַנַּ֣עַר NAS: saying, [Deal] gently for my sake with the young man KJV: saying, [Deal] gently for my sake with the young man, INT: and Ittai saying gently the young Absalom
1 Kings 21:27 HEB:בַּשָּׂ֔ק וַיְהַלֵּ֖ךְ אַֽט׃ ס NAS: and went about despondently. KJV: in sackcloth, and went softly. INT: sackcloth and went despondently
Job 15:11 HEB:אֵ֑ל וְ֝דָבָ֗ר לָאַ֥ט עִמָּֽךְ׃ NAS: for you, Even the word [spoken] gently with you? KJV: small with thee? is there any secret thing INT: of God the word gently with
Isaiah 8:6 HEB:הַשִּׁלֹ֔חַ הַהֹלְכִ֖ים לְאַ֑ט וּמְשׂ֥וֹשׂ אֶת־ NAS: have rejected the gently flowing KJV: that go softly, and rejoice INT: of Shiloah flowing the gently and rejoice Rezin
Isaiah 19:3 HEB:הָֽאֱלִילִים֙ וְאֶל־ הָ֣אִטִּ֔ים וְאֶל־ הָאֹב֖וֹת KJV: to the idols, and to the charmers, and to them that have familiar spirits, INT: idols and to the charmers and to mediums
Hosea 11:4 HEB:עַ֣ל לְחֵיהֶ֑ם וְאַ֥ט אֵלָ֖יו אוֹכִֽיל׃ INT: from their jaws secret to fed
, 
send, 
messenger, Ethiopic 
send a messenger, see 
be sent, wait on, minister; 
=Hebrew