Follow the below mentioned steps to remove eBay Professional Importer app from your Shopify store.
Step 1: Login to your Shopify store admin and click on the left menu: Apps.
Step 2: Now click on the trash icon as highlighted in the below screenshot.
Step 3: Now it will ask you for the reason of removing the app. Just choose a relevant option and click on the red Delete button to complete uninstall process.