Hi,
If you want to remove all tabs or any particular tab for example description and reviews, then use the below code in the functions.php:

add_filter( 'woocommerce_product_tabs', 'FindNerd_remove_product_items', 58 );
function findnerd_remove_product_items( $items ) {
    unset( $items['description'] );                      // To remove description item
    unset( $items['reviews'] );                           //To remove reviews item
    unset( $items['additional_information'] );      //To remove additional information item
    return $items;
}

In above code- woocommerce_product_tabs- is a predefined function, which refers to the action you are performing.
FindNerd_remove_product_items' 58- FindNerd_remove_product_items- is a built-in function, this you can rename it according to your wish and 58 is a position where your function hits to perform function.

Or if you want to remove the reviews tab so that only product description appears add this single line code to your custom.css file-

.woocommerce .woocommerce-tabs ul.tabs {display:none !important}