Fastidious is an adjective that means very attentive and concerned about accuracy. 

Coming from the Middle English period, our word of the day gets its origin from the Latin word fastidiosus (foss tee dee OH soose) which initially meant ‘disagreeable.’ By the late 17th century, the word shifted into fastidious and took on its current meaning. Here it is in use:

I can be pretty fastidious when it comes to doing my job as the local baseball team’s scorekeeper. If I wasn’t extremely careful and attentive to it, we could award a victory to the wrong team.