from The Century Dictionary and Cyclopedia
- n. A member of the inopportunist or opposition party; one who disapproves of a certain policy on the ground of its inopportuneness; specifically, one who was opposed to the declaration of the dogma of papal infallibility at the Vatican Council in 1870, on the ground that its publication was inopportune.
- Belonging to the inopportunists.
Sorry, no etymologies found.
It's an eccentric choice for this assemblage of the most important American writers, because Agee's obvious talent went largely unrealized, thanks to his prodigality (Macdonald aptly judged him "a shameless inopportunist") and consequent death at age forty-five.