'Callously' definitions:

Definition of 'callously'

adverb

In a callous way; "he callously exploited their feelings" [syn: callously, unfeelingly]

From: GCIDE

Callous \Cal"lous\, a. [L. callosus callous hard, fr. callum, callus, callous skin: cf. F. calleux.]
1. Hardened; indurated. "A callous hand." --Goldsmith. "A callous ulcer." --Dunglison. [1913 Webster]
2. Hardened in mind; insensible; unfeeling; unsusceptible. "The callous diplomatist." --Macaulay. [1913 Webster]
It is an immense blessing to be perfectly callous to ridicule. --T. Arnold.
Syn: Obdurate; hard; hardened; indurated; insensible; unfeeling; unsusceptible. See Obdurate. -- {Cal"lous*ly}, adv. [1913 Webster]
A callousness and numbness of soul. --Bentley. [1913 Webster]