This is the 611th most frequent Chinese word.
仅
"仅" means "only" or "merely."
Here, '仅' is used as 'only', indicating a restriction or limiting the amount, expressing that he only needed two days.
他仅用了两天就完成了工作。
He completed the work in just two days.
In this sentence, '仅' is part of the compound phrase '不仅', which means 'not only' and is used to expand on two related ideas.
这场比赛不仅激烈，还非常有趣。
Not only was this match intense, but it was also very interesting.
Here, '仅' is again used as 'only', emphasizing a restricting condition.