These two words seems related to each other. I often heard "he is mochel the tnay (the condition)" or " girsha stam". I think it means something like he abandoned his condition but I can't find the exact translation. For the second one, i think it has something to do with a divorce but I am not sure.
"Girsha stam" means he divorced her without stating any conditions.
Mochel means forgiving, so "he is forgiving the condition" or if you wanted to say it in proper English "he forgives the condition" or "he forgoes the condition." In other words, he waives it (or is presumed to have waived it, depending on the context).