It depends how you define it.
If it is defined as avoiding action in case it is not perfect, fussing needlessly over detail and thereby confounding the project, or being craven about the outcome or others' reactions, then certainly it's a defect.
If it's the desire to believe, think, and act perfectly: then no, it's a great virtue, because perfection is the lodestar of all successful endeavour.
A common by-way in recovery is to not take action, or to take next to no action, on the grounds that one of my character defects is perfectionism, character defects are bad, so I'm going to sit on my behind, because to push myself would be to practise my perfectionism.
This, of course, is rationalisation for sloth.
If such a rationale is a temptation, the advice would be to: work very hard to eliminate every other defect first, and only once all other defects are eliminated turn to work on perfectionism.