This is the 619th most frequent Japanese word.
ま
"ま" (ma) can mean "interval," "space," "pause," or "timing," depending on context.
Here, 'ま' is part of the verb 'まつ' (to wait) in its command form.
まってください。
Please wait.
In this sentence, 'ま' is present as part of the adverb 'まったく,' which means 'completely' or 'absolutely.'
彼の話はまったく信じられない。
I absolutely can't believe his story.
The word 'ま' in '一まい上手' is used as part of a compound phrase referring to someone's superiority.