4 And he saith to them, `Is it lawful on the sabbaths to do good, or to do evil? life to save, or to kill (ἀποκτεῖναι)?' but they were silent. [YLT]
9 Then said Jesus unto them, `I will question you something: Is it lawful on the sabbaths to do good, or to do evil? life to save or to kill (ἀπολέσαι)?' [YLT]
9 Then said Jesus unto them, I will ask you one thing; Is it lawful on the sabbath days to do good, or to do evil? to save life, or to destroy (ἀπολέσαι) it? [KJV]
28 `And be not afraid of those killing (ἀποκτεῖναι) the body, and are not able to kill (ἀποκτεῖναι) the soul, but fear rather Him who is able both soul and body to destroy (ἀπολέσαι) in gehenna. [YLT]
Mark 3:4 and Luke 6:9 use ἀποκτεῖναι and ἀπολέσαι respectively to report the same situation. Matthew 10:28 is more interesting because the two verbs are used in the same context, but apparently to describe different kinds of experiences.
Are kill (ἀποκτεῖναι) and destroy (ἀπολέσαι) synonyms? Does the answer depend on the context?