“The word ‘imputation,’ according to the Scriptural usage, denotes an attributing of something to a person, or a charging of one with anything, or a setting of something to one's account. This takes place sometimes in a judicial manner, so that the thing imputed becomes a ground of reward or punishment.” —CW Hodge
the sin of Adam is imputed to all his descendants, i.e., it is reckoned as theirs, and they are dealt with therefore as guilty
the righteousness of Christ is imputed to them that believe in him, or so attributed to them as to be considered their own
our sins were imputed to Christ, i.e., he assumed our “law-place,” undertook to answer the demands of justice for our sins
In all these cases, the nature of imputation is the same (Romans 5:12-19; compare Philemon 1:18-19).