Pick-litter is often associated with the act of cleaning up litter, but there are several synonyms that can be used interchangeably depending on the situation. One such synonym is "litter-pick," which also refers to the process of cleaning up litter. Another synonym is "litter collection," which can be used to describe the act of gathering litter that has been discarded. "Litter clearance" is another synonym that can be used to mean the same thing. Alternatively, you could use "litter removal" or "litter cleanup," as both imply the act of ridding an area of litter. Whatever term you use, the message remains the same: it's important to keep our environment clean and free of litter.