Translation:He does not open the door
juryrigging already answered but I wanted to point out that -u- added to the end of a verb before the -a often creates a kind of opposite meaning.
It is like undoing it - you have to close (-funga) the door before you are able to open (-fungua) it again.
Yeah, it's good to remember it like -u- = un-
With open and close, I was getting them mixed up for a while because I kept forgetting which one is the inherent one (ie. do you close and unclose doors or open and unopen doors?) but I'm comfortable with it now. I'll still probably mix them up though because I often mix up opposites in any language, which is a bit weird and I wonder what's going on in my brain.
Polish has a few examples of opposites differing by just one letter. I used to get confused between przyszłość/'future' and przeszłość/'past', and wejść/'enter' and wyjść/'leave'.
In the present tense (and only in the present tense), the verb end “-a” changes to “-i” in negated verbs.
Check out the Negations chapter in the excellent 2Seeds Swahili course: