Not sure that I was familiar with this word, which comes up in this thorough exploration of the constitutional question surrounding the conviction, out of office, of an official impeached while in office.
The author seems to use it in this sentence, and one a few paragraphs down, to mean “plausible” while wiktionary’s definition is more like “specious”:
“So far as I can see, Bobbitt’s position rests primarily on a colorable—but tenuous—argument from the text of the Constitution’s impeachment clauses.”
.i`` * ^ / . . . . . ` `~ 