Refused point blank: To say no in a firm and direct way.
example: I´m refused point blank to eat meat again.

Kettle or urn: Metal containers used for making tea or coffee.
example: When I went to the National Gallery in London I saw an old kettle used by the Queen Victoria.

Endorse: Say in public or in an ad that you like a product.

example: A brand of cruelty free make-up asked Miley Cyrus to endorse their products.

Freebies: Something someone gives you that you don´t have to pay for.

example: When I bought a matcha spread they gave me more vegan spreads, they told me they were freebies, so I didn't need to pay more for them.
Understand nuances: Understand slight differences that may be difficult to notice but are important.
example: When I go to a restaurant the most of the waitresses don´t understand the nuance between vegetarian and vegan.

In my opinion this topics are the most significant because they are essential for the other ones, you need the knowledge, the bases so you use them for the other topics.