un‧ho‧ly [no comparative]
an agreement between two people or organizations who would not normally work together, usually for a bad purpose
2 [only before noun] informal
bad and extreme:
An unholy row broke out between two of the men drinking in the bar.
an unholy mess
not holy, or not respecting what is holy
pleasure etc that you get from someone else's suffering:
He was taking an unholy delight in humiliating Sarah.