Inofficious

1. a. Regardless of natural obligation; contrary to natural duty; unkind; — commonly said of a testament made without regard to natural obligation, or by which a child is unjustly deprived of inheritance.
2. a. Indifferent to obligation or duty.
3. a. Not officious; not civil or attentive.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.