A "thorough checkup" means a careful examination or inspection to make sure everything is healthy or working properly.
Sentences with «thorough checkup»
I am going to self pay the endocrinologist for a more thorough checkup. (forefronthealth.com)
To give your relationship a more thorough checkup, check out my comprehensive relationship checkup. (strengthenyourrelationship.com)
It's a good idea to call your doctor if your child is displaying signs of dehydration so he can do a thorough checkup and offer the most appropriate method of rehydration. (whattoexpect.com)