'utterly complex' is correct and usable in written English.
You can use it to describe something when you want to emphasize that it is very complex or hard to understand. For example, "The professor's lecture on quantum mechanics was utterly complex."
The relationship with Pakistan is utterly complex, and totally fractured.
William Eggleston's Guide was, says Parr, 'lambasted at the time for being crude and simplistic, like Robert Frank's Americans before it, when in fact, it was both alarmingly simple and utterly complex.
I was struck again by how utterly complex a woman's relationship to her body is and how competitive women are with each other.
Like all forms of modern mass transport, cruise liners are utterly dependent on complex electronic devices to steer them – and on electricity to run these systems.
And if you've already thrown caution to the credit card, Marks & Sparks has CVNE's utterly mellow, endlessly complex and savoury classic Real de Asua 2004 (£46).
It is utterly shocking that complex and important decisions are routinely made on hidden scientific data, and it leads to expensive and potentially life-threatening mistakes.
The tone of Adult Onset is frank and acidly funny, not unlike Alison Bechdel's Fun Home, and the writing is utterly engaging and complex.
The biggest thing, and Ms. Weaver does get it right, is that Pakistan is an afflicted, complex, utterly fascinating country, and despite her wobbly beginning, she provides an intimate portrait of the place.
Haeckel, who is best known for developing the theory of recapitulation ("ontogeny recapitulates phylogeny"), was also a masterful artist, and his illustrated studies of everything from jellyfish to moths and praying mantids, executed with painstaking precision, reveal a natural world that is utterly mystifying and complex.
According to Naomi Wolf's fascinating new book, Vagina: A New Biography, our nether regions are deeply complex, utterly unique playgrounds of pleasure that are able infuse us with creativity and joy.
Psychologically complex, and utterly terrifying.
