Minhal, pronounced as [(MIN)t] + [(HU)g + p(L)ay], is a non-Quranic Arabic word that means "strong downpour of rain". It is spelled as منهل like you wrote. It is acceptable to use it as a name since it has a good meaning. It can also be spelled as Menhal, Mynhal.
There is a similar sounding word, Minhaal, which you can read about here: What is the meaning of Minhaal?