Stop up and Tack on

Stop up verb - To prevent passage through by filling with something.

Tack on and stop up are semantically related. In some cases you can use "Tack on" instead a verb "Stop up".

Tack on verb - To join (something) to a mass, quantity, or number so as to bring about an overall increase.

Stop up and tack on are semantically related. Sometimes you can use "Stop up" instead a verb "Tack on".