The idiomatic examples in Korean are cases of the PNI sentences in which the direct object is incorporated to the verb. The distributional properties of accusative case drop phenomenon in Korean object-verb idioms can be analyzed on a par with pseudo noun incorporation (PNI) found in Niuean discussed by Massam (2001). This challenges the empirical basis for any head-movement account (Baker 1988, 2009). Therefore, head movement does not extend straightforwardly to PNI structures. There are four essential traits of PNIed direct objects in Korean: (i) omission of case-markers, (ii) low scope, (iii) ban on extraction out of the VP, and (iv) phrasal elements such as NPs, NumPs and DPs. The PNIed version forms a separate word/phrase and there is an interaction at the boundaries between PNIed direct objects and Vs, which is testified by the verb stranding VP-ellipsis (VVPE). If the PNIed direct object is extracted out of the VP, the sentence simply crashes in derivation. Importantly, it has been tested by Barrie’s three-pronged diagnostics for (pseudo)-incorporated nouns ((P)INs) whether the data in question confirms to PNI. The caseless direct object in question readily undergoes PNI to the verb, showing obligatory low scope over the subject.