IPA: //ˌpoʊstɪnˈdʒɛkʃən//
KK: /ˌpoʊstɪnˈdʒɛkʃən/
Referring to the period or condition that occurs after a medical injection has been given.
The patient experienced some discomfort in the postinjection phase.
Postinjection → It is formed from "post-" (meaning after) and "injection" (from Latin "iniectio", meaning to throw in). The word "postinjection" refers to something that occurs after an injection.
Think of something happening 'after' ('post-') a 'throwing in' ('injection') — that's what postinjection means.