Troweling is the process of spreading and smoothing a surface with a trowel. There are several synonyms for this word, depending on the context in which it is used. Some of the synonyms include 'smoothing,' 'finishing,' 'polishing,' 'leveling,' 'plastering,' and 'spackling.' These words all describe the action of using a trowel to even out a surface and make it smoother. While the specific word chosen will depend on the situation and the speaker's preference, they all convey the same general meaning of using a trowel to smooth out and perfect the surface of a material.