It is not simple nor complex. Because it does not have a dependent clause, but a University of Cambridge Grammar book also says a compound sentence must consist of two independent clauses. If there are more than two independent clauses then rewrite them as two sentences.

What is a complex word?

A complex word is defined by the Siteimprove algorithm as a polysyllabic word, which is a word made up of more than three syllables.

What are some complex words?