The neighborhood recently installed security cameras because two sex-offenders were registered nearby.

sex-offenders 是由 sex（性）和 offenders（犯罪者）组成的复合词。offender 来自动词 offend（冒犯、犯罪）加上后缀 -er（表示人），指"犯罪者"。 sex-offenders 特指"性犯罪者"，即犯下与性有关的罪行的人。