Rashi (on 25:25) suggests that the basis for the name of Esav is that he was born made (the word aseh) as his hair was like a grown up. This explanation relates the name to the type of hair, but 25:25 does not refer to Esav having hair like a grown up.
In a fascinating article, David Yellen (1927, pp. 453-455) notes that when Hebrew was a living language, some words which had two meanings were known by everyone who spoke the language, but after Hebrew stopped being spoken on a daily basis, only the main definition of a word was remembered, while the secondary meanings of word were forgotten. Yellin gives twenty-two examples, and one of them is the word aseh. He shows from several passages in Tanakh that the word aseh had a secondary meaning of to cover, and then he explains that the name Esav refers to him being born covered with hair.
This same idea is also relevant to understanding Devarim 21:12, which Yellin did not mention, and which records instructions how the captive woman is to be treated. Devarim 21:12 records that the nails of the captive foreign woman were to be done, asah. What does this mean? Rashi and Ibn Ezra (on 21:12) write that this means that the captive woman was to let her nails grow which would make the woman repulsive. How can the word asah, which refers to doing something, mean to let the nails grow since that is a passive action? It is also not clear how letting the nails grow for a month will make the woman repulsive since they will not grow that much. Instead, following, Yellen's idea, the idea could be that the nails of the captured woman were to be covered, which might make her less attractive.
Bereshit 25:26 then records that when Yaakov was born, he was holding onto the heel (ekev) of Esav, and he was called Yaakov. In this case, it seems that the name Yaakov is related to the heel, see Rashi on 25:26. Yet, then the yud in the beginning of the name is left unexplained. Cassuto (1965, p. 717) notes that variations of the name Yaakov, such as Ya-akh-qu-ub-il(um) have been found on tablets in 18th century BCE in Mesopotamia and in Egypt at around the same time when Yaakov was living. He writes that Yaakov is a short version of the term Yaakov-kel, and the name Yaakov has the meaning of a prayer that the person should go with/ follow G-d, which has the idea of a prayer that G-d should protect Yaakov. This beautiful reason for the name Yaakov, as suggested by Cassuto, might explain why the Torah continues to use the name Yaakov, even after G-d gave Yaakov the additional name of Yisrael, 35:10.
Bereshit 25:26 then records that when Yaakov was born, he was holding onto the heel (ekev) of Esav, and he was called Yaakov. In this case, it seems that the name Yaakov is related to the heel, see Rashi on 25:26. Yet, then the yud in the beginning of the name is left unexplained. Cassuto (1965, p. 717) notes that variations of the name Yaakov, such as Ya-akh-qu-ub-il(um) have been found on tablets in 18th century BCE in Mesopotamia and in Egypt at around the same time when Yaakov was living. He writes that Yaakov is a short version of the term Yaakov-kel, and the name Yaakov has the meaning of a prayer that the person should go with/ follow G-d, which has the idea of a prayer that G-d should protect Yaakov. This beautiful reason for the name Yaakov, as suggested by Cassuto, might explain why the Torah continues to use the name Yaakov, even after G-d gave Yaakov the additional name of Yisrael, 35:10.
Bibliography:
Cassuto, Umberto (1883-1951), 1965, Yaakov, in Encyclopedia Mikrait, edited by Naftali Hertz Tur-Sinai, Shmuel Yavin and Binyamin Mazer, Vol. 3, Jerusalem: Bialik Institute, pp. 716-722.
Yellin, David, 1927, Forgotten meanings of Hebrew roots in the Bible, in Jewish Studies in Memory of Israel Abrahams, New York: The Alexander Kohut Memorial Foundation, Press of the Jewish Institute of Religion, pp. 441-458.