Meaning : Deeply involved.
Example :
Neck-deep in work.
Up to their necks in debt.
Synonyms : neck-deep, up to her neck, up to my neck, up to our necks, up to their necks, up to your neck
Up to his neck ka meaning, vilom shabd, paryayvachi aur samanarthi shabd in Marathi. Up to his neck ka matlab kya hota hai?