mardum : 'A man; men, people; — a polite or civilized man; — pupil (of the eye)'. (Platts p.1022)
aab : 'Water; water or lustre (in gems); ... sparkle, lustre'. (Platts p.2)
For more on Ghalib's unpublished verses, see the discussion in {4,8x}. See also the overview index.
An older name for rabies was hydrophobia, which means 'fear of water'; the disease was named after one of its most characteristic symptoms. Dog bites are proverbially (and also actually) the way rabies is most often transmitted to humans.
On this simple factual basis Ghalib has framed an extraordinary verse. The key to it is the word mardum , with its two meanings of 'a man, men, people' and 'pupil of the eye' (see the definition above).
If we take mardum to mean 'a man, men, people', then the speaker fears people the way someone with rabies fears water. And in fact the shiny flat surface of the mirror can well be said to resemble water. (This is Gyan Chand's point about the implicit wordplay with aab .) But the real punch comes with the mirror's reflective surface, for in it the speaker will see himself-- he who is 'a man', or even 'a polite or civilized man'. Perhaps this is an overreaction-- humans have injured him, and now he fears every sight of a human face, even his own image in a mirror ('Once bitten, twice shy').
But even more provocatively, the speaker's fear may be appropriate. He has been injured, 'bitten', by a man-- and he himself is a man. Might there not be something inherently dangerous about the whole species? Whenever and wherever he sees a human face and feels panic, perhaps he is right.
Then, if we take mardum to mean 'pupil of the eye', the speaker fears the mirror because it will show him his face at close range. He has been 'bitten by the pupil of the eye'. It's been shown that prolonged gazing into someone's eyes, the 'eye-contact effect', has a remarkably powerful effect on the brain. Perhaps the speaker has previously felt the potency of such an effect with others-- and now fears to experience it even (or especially?) with his own image in the mirror. Or perhaps he has already had this experience when he looked into the mirror-- and now that he knows what it's like, he's panicked at the thought of experiencing it again.
It's really a devastating verse.
Gyan Chand:
If anyone has been bitten by a mad dog, then after some days he becomes mad and begins to be afraid of water. I have been tormented by mankind; thus I fear even a mirror. Because in it the reflection of a man is visible. I have so much suspicion of mankind that I am panicked even by my own reflection. In a mirror there is aab (shininess); thus it has a similitude with aab , or water. mardum-gaziidah = having been bitten by a man.
== Gyan Chand, p. 515