Is "Metaphorically" a transition word?

It can be.

As in..."Metaphorically, the disguise represents evil."

It's an adverb, but it can work as a transition, too.

No, "metaphorically" is not typically considered a transition word. Transition words are used to connect ideas, sentences, or paragraphs by indicating relationships between them, such as cause and effect, contrast, comparison, or sequence. Examples of common transition words include "however," "therefore," "in addition," "because," and "however."

On the other hand, "metaphorically" is an adverb that is used to describe something in a metaphorical or figurative sense rather than in a literal or straightforward manner. It is not used to establish a connection between ideas or provide a smooth transition in writing. Instead, it is used to add color, depth, or imagination to language.