There are some contradictions in your criteria, e.g you have >3 and <3. What happens if it is 3? I have allowed for some of these but anything over 1 will get a proper case Slow Moving and anything below or equal to 1 will get an all lower case 'slow moving'. (That would be too subtle a difference for me!)
I have also allowed the first clause to show nothing if the cell it relies on is blank.
=IF(A1="","",IF(A1>=3,"Fast Moving",IF(A1>1,"Slow Moving","slow moving")))
Microsoft MVP, Excel