Psalms 5:1

on nehiloth Menachem interpreted all of them: nehiloth, alamoth, gittith, jeduthun, that they are all names of musical instruments, and the melody of the psalm was according to the melody fit for that instrument. However, [in the] Midrash Aggadah (Mid. Ps. 5:1,2,4) some explain “nehiloth” as an expression of heritage, but that is not the meaning of the word; moreover, the contents of the psalm do not deal with heritage. It is, however, possible to interpret נחלות as troops, like “a swarm (נחיל) of bees,” (Bava Kamma 114a, 81b), and like (II Sam. 22:5), “Bands (נחלי) of scoundrels would affright me,” which Jonathan renders: Bands (סיען) of sinners. [This is] a prayer concerning the bands of the enemies that come upon Israel, and the Psalmist recited this psalm on behalf of all Israel.

For the leader (el ha-nechilot): [Regarding the preposition] el (אֶל): It is like al (עַל - upon/concerning) in meaning here. Similar [is the usage in (I Samuel 1:10)]: "And she prayed unto/concerning (al) Ad-nai." [And compare (I Samuel 1:27)]: "Concerning (el) this child [I prayed]." [This is] the opposite [of their usual distinction: el normally means 'to/towards' while al means 'upon/about']. And the [letter] Alef (א) does not interchange with the [letter] Ayin (ע), but rather the letters Alef, Heh, Vav, Yod (אהו"י - the weak letters) are the ones that interchange, and [also] Shin (ש) with Samekh (ס), because they are close in their place of articulation.

And ha-nechilot (הַנְּחִילוֹת): [This is likely] the beginning [words or tune name] of a liturgical poem/song (piyyut). Perhaps it is derived from the root [N-Ch-L, נ-ח-ל, meaning 'to inherit'], as in [a phrase like (Numbers 34:17)] "they shall divide the inheritance (yinchalu) for you." [The noun formation Nechilot is formed] in the manner of [a segolate noun like (I Kings 19:8)] "ha-achilah ha-hi" (האכילה ההיא - that eating).

For the Chief Musician: To the Nehiloth. A Psalm of David. – I have already explained the meaning of the Nehiloth and other kinds of music in the previous Psalm. Our teacher Hai, of blessed memory, explained the word (nehiloth) from the expression nehil (נהיל), (meaning) “a swarm” of bees, in the words of our sages of blessed memory (Mishnah, Baba Kamma 10:2). He means that its music was like the buzzing of bees. This Psalm is also likewise directed against David's enemies, those in Israel who were ill-disposed to him. Our rabbis of blessed memory have said (Midrash, Shoher Tob, ad loc.) that he uttered it against his adversaries Doeg and Ahithophel.