Gmail does not offer a feature to completely block the senders. You can only spam the message or you can only delete the messages.
You can set filters to do this action.
If you want any emails to be deleted in feature, create a filter to delete the messages automatically
To create a delete filter,
Copy the senders address that you want to automatically delete
Select �Create Filter� appearing next to the Search button 
Enter the senders email address 
Click Next Step
Choose Delete
Then click Create filter 
So messages coming from now from the address what you specified will automatically be sent to Trash
You can also choose from the Inbox view and set the filter
Open your Inbox
Choose the message that you want to delete automatically
Then click more action 
You will see a drop down menu with many options
Click Filter Messages like this
Gmail automatically opens the filter option with the email address, so you do not need to copy and paste
You need to follow the other steps of setting the filters like choose delete and create filter
If you have any question or suggestion, please post a comment