As digibudll has said, there is really nothing you can do about unsharp/blurry footage. Some processes may improve it but it's never going to look good.
If it is only in a couple of places in the whole video you could either leave it there and try to ignore it or else remove it entirely ........ possibly even the entire clip.
Many amateurs (including me) have an irrational love of every second of video we shoot and are loathe to discard any of it.
This generally results in films that are many times longer than they should be, lack pace and are generally boring to anyone other than close friends and family.
So ask yourself whether that particular clip needs to be in the video at all .......... and if not, trash it.
P.S. If the comments about most of us amateurs don't apply to you, please accept my sincerest apologies. 😉