You get 29/30 when you accidentally use the same answer twice. I have done that a couple of times.
Part 3 often uses links that are not apparent between the two words directly, but are there because of some shared word in the background. They can be from alternative definitions of the same word, or from a list of synonyms (and I can't be the only person who has noticed that some synonyms in those dictionary lists are a lot closer to the original word than others!), and so on.
Since I grew up knowing that a joint is a reference to marijuana, and have since learned that spliff is another one, I see that as quite clear for a link. It's not in the definition of each term, but it's there.
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(Editor in Humanities, Religion, Literature and For Children)
That's all, folks!