Keyword Analysis & Research: what does return to sender refused mean

Keyword Analysis

Keyword	CPC	PCC	Volume	Score	Length of keyword
what does return to sender refused mean	0.38	0.1	8155	100	39
what	1.15	0.4	7920	99	4
does	0.52	0.3	5019	84	4
return	0.45	0.4	6078	52	6
to	0.47	0.8	2475	55	2
sender	1.17	1	1050	27	6
refused	0.33	0.3	7404	46	7
mean	1.02	0.2	1421	26	4

Keyword	CPC	PCC	Volume	Score
what does return to sender refused mean	0.68	0.5	760	88