GO:0010521

Stops, prevents or reduces the activity of a telomerase. Telomerase catalyzes the reaction: deoxynucleoside triphosphate + DNA(n) = diphosphate + DNA(n+1). Catalyzes extension of the 3'- end of a DNA strand by one deoxynucleotide at a time using an internal RNA template that encodes the telomeric repeat sequence. [GOC:dph, GOC:krc, GOC:tb]