easy-going vs easy going
Solution 1:
Use the hyphen or the solid form to mean 'relaxed': you are using an adjective, and many compound adjectives which include verbs tend to be at least hyphenated wherever there's even a possibility that the reader might parse the compound could be misread as two separate words (assuming the author is paying attention).
Going is also a noun which can refer to the quality of a journey, especially the rate of progress, and "easy going" could mean a straightforward and effortless journey.
Solution 2:
I know what you mean here. Hyphens are essential to avoid ambiguity, especially without compound adjectives: for example a hyphen is the difference between a man eating squid and a man-eating squid. Therefore, I would suggest that Clive is easy going without the hyphen as there is no confusion there.