FilterSMS app will filter your incoming sms messages and add them to spam/junk section based on the blacklist of words created by you.
Here is how it works:
1. You activate FilterSMS extension in Settings / Messages / Unknown & spam.
2. You add keywords to the Filter Spam SMS blacklist.
3. Thats it :)
Any sms you will receive from a phone number that is not in your contacts list will be automatically filtered by FilterSMS.
If the sms message contains any keywords from your defined blacklist it will be filtered and added to junk in Messages.
Twitter Support: @filtersmsApp