My first instinct was mimea, and that is indeed the case.
A lot of plants and parts of nature fall into the M/Mi classes -- mti/miti (tree(s)), mchungwa/michungwa (orange tree(s), not to be confused with its fruit, chungwa/machungwa, which belongs to Ji/Ma), mto/mito (river(s)), mlima/milima (mountain(s)), etc. There are exceptions, but if you aren't sure M/Mi a good place to start for nouns of this type.
They are pronounced separately:
(m)ME-a (two syllables, and the first is prenasalised)
Here is a video with pronunciations that contain prenasalised consonants with m sound. We can see only in the case of mbwa (dog) the stress is on the m because this word is monosyllabic.
Nope, it's three syllables: m-me-a [m̩.ˈmɛ.(j)ɑ]
The only prenasalised consonants in Swahili are
Prenasalised plosives: /ⁿb ⁿd ⁿd͡ʒ ⁿg/ (= mb nd nj ng) Prenasalised fricatives: /ⁿv ⁿz/ (= mv nz)
In other cases, "m" before another consonant (other than "y" or "w") is simply a syllabic nasal. If it's the second last syllable, it can be stressed, as in
mka, but if it's not, it is not, such as m