offhand

As an adjective offhand

is without planning or thinking ahead.

As an adverb offhand

is right away, immediately, without thinking about it.

As a noun shame is

uncomfortable]] or painful feeling due to recognition or consciousness of impropriety, dishonor or other wrong in the opinion of the person experiencing the feeling it is caused by awareness of exposure of circumstances of [[unworthy|unworthiness or of improper or indecent conduct.

As an interjection shame is

a cry of admonition for the subject of a speech, often used reduplicated, especially in political debates.

As a verb shame is

to feel shame, be ashamed.

As adjectives the difference between haphazard and offhand

is that haphazard is random; chaotic; incomplete; not thorough, constant, or consistent while offhand is without planning or thinking ahead.

As an adverb offhand is

right away, immediately, without thinking about it.