Which fallacy is committed in the following argument? "Grades awarded to a student are not truly reflective of the subtle nuances of the student's performance. Therefore, students' work should not be graded at all."

The word "reflective" is used in two different senses, which is equivocation.

The premise says grades do not capture the subtle, fine-grained nuances of performance.

This is only a claim about incomplete or partial reflection, not zero reflection.

The conclusion silently shifts to grades reflecting nothing, so grading should stop.

By sliding from "not fully reflective" to "not reflective at all", the term changes meaning.

An argument that trades on such a shift of sense commits the fallacy of equivocation.