IPA: /ɪkˈsplɛtəri/
KK: /ɛkˈsplɛtəri/
Relating to something that is added to fill out or complete a sentence or expression, often unnecessarily.
The poem included several expletory phrases that did not add meaning to the overall message.
Expletory → It is formed from "expletus" (from Latin, meaning filled out or completed) and the suffix "-ory" (meaning relating to or characterized by). The word "expletory" refers to something that serves to fill out or complete, often in the context of language or grammar.
Think of something that 'fills out' ('expletus') and is 'related to' ('-ory') — that's why expletory means something that serves to complete or fill out.