not unlike

English Language Proficiency Tests, Advanced Level

ESL/EFL Test #880 [color=blue]“The Blue Gotto of Capri”, question 5

Visitors are encouraged by the guide to put their hand in the water; they are astounded at seeing it glow strangely in the light, not unlike the of a star.

(a) development
(b) appearanace
(c) temperature
(d) luminosity

English Language Proficiency Tests, Advanced Level

ESL/EFL Test #880 [color=blue]“The Blue Gotto of Capri”, answer 5

Visitors are encouraged by the guide to put their hand in the water; they are astounded at seeing it glow strangely in the light, not unlike the luminosity of a star.

Correct answer: (d) luminosity
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not unlike? Isn’t that the same as “like”?

Yes.
You know that English is diverse.
There are many vocabulary and phrase choices.

This rhetorical device is called ‘litotes’.