Some later scholars used tafsir for determining a meaning supported by decisive evidence, and taʾwil for preferring one plausible meaning over another without claiming certainty.
Where language and context decisively establish one sense, an interpretation can be stated with confidence. Where multiple serious readings remain possible, textual and contextual indications may favor one, but its inferential status should not be concealed.
This is a particular later terminology, not a universal definition followed by every scholar in every era. The key distinction concerns decisive determination versus evidence-based preference between possibilities.