GOOK-goo
If you know IPA [ˈgʊkːʊ]

Remember that the kk refers to a long stop that straddles the syllable boundary.

A single morpheme (no divisible word parts).

If you are learning Kuninjku (I) or Kune (E) dialects at Maningrida beware, there is a different word for water, kunronj pronounced GOON-rony or in IPA [gʊnrɔɲ]. The word for water in Bininj Kunwok dialects is a real linguistic shibboleth— a way of speaking that marks membership of a particular speech community.

Bedda Kunbarlanja kukku kabirriyime, ngad Kuninjku ngarriyime kunronj.
Those Gunbalanya people say 'kukku' for water whilst we Kuninjku people say 'kunronj'.

If you want to say 'in the water' or 'into the water' the initial consonant softens to 'w' after a locative prefix ku-:
kuwukku
ku- 'in/at' -wukku 'water'
In Kuninjku it would be kuronj 'in the water'.

We have already mentioned the concept of noun incorporation where a noun stem can be fixed between a pronoun prefix and a verb. However for the word water, there is a completely different word for the incorporated form, -bo-.

ngabonan 'I can see water'
nga-bo-nan 'I-water-see'
kanbowo 'give me water'
kan-bo-wo 'you>me-water-give.imperative'
Kukku, kanbowo! Water, give me water.
Kunronj, kanbowo. Water, give me water.

If you are learning Kune dialect, the incorporated form is not -bo- but -kolh-.
Ngakolhngun 'I'll have a drink'
nga-kolh-ngun 'I-water-consume'