The word "rosing" is not common and may not have many synonyms. However, some possible alternatives to the word "rosing" could be "rosining", "resinating", or "pitching". "Rosining" refers to the process of applying rosin to a bow for string instruments, such as a violin or cello. "Resinating" and "pitching" both refer to the use of pitch or tar to waterproof or seal a surface. While these words may have slightly different meanings, they could potentially be used as synonyms for "rosing" in certain contexts, such as in discussions of outdoor sports or woodworking.