S. R. Faruqi:

Here, with regard to meaning there's nothing special. Although the affinities are fine: (1) ḥusn , ḳhvush , rū . (2) aḳhtarī , māh , mushtarī . (3) māh , tāb (meaning 'radiance'). In both lines the insha'iyah style has created pleasure; otherwise, the idea is commonplace.

Indeed, in the first line to say ḳhvush-aḳhtarī kī with the meaning of 'to speak about her happy-starredness, to express her situation' is fresh. In the whole verse, the tone is as if someone has investigated some new thing, or obtained a new thing, and with great fervor and pomp wants to speak about it as well.

The expression ḳhvush-aḳhtarī is very fresh and interesting. Mir has used it one more time as well, in the sixth divan [{1837,2}]:

vaṣl kyūñ-kar ho us ḳhvush-aḳhtar kā
jażb nāqiṣ hai aur t̤āliʿ shūm

[how would there be union with that happy-starred one?
the attraction is deficient, and the stars unlucky]

Here too, in the meaning there's nothing special, but the zila of the astrological terms ( vaṣl , aḳhtar , jażb , t̤āliʿ , shūm ) has been versified very well.

The problem nevertheless remains the same: what is the meaning of ḳhvush-aḳhtar ? Farid Ahmad Barkati has devised for it the meaning of 'fortunate'; this same meaning is in Platts and urdū luġhat tārīḳhī uṣūl par and Steingass. The difficulty is that for calling the beloved 'fortunate' there's neither any context nor any 'warrant'. [A discussion of other Urdu dictionaries that prove unhelpful.] To call the beloved 'fortunate' is devoid of pleasure, as long as it has no metaphorical meaning. And of metaphorical meaning there's no trace in the dictionaries.

Then, consider this as well: that in the present verse if ḳhvush-aḳhtarī is taken to mean 'fortunate', then the speaker seems to be more of an astrologer than a lover: he wants to tell us about the beloved's auspicious fortune. Clearly this meaning is here inappropriate and devoid of pleasure.

Thus it's also clear that in both these verses Mir used ḳhvush-aḳhtarī and ḳhvush-aḳhtar to mean 'beauty' and 'beautiful'. Now whether this is his own invention, or is on the 'warrant' of some Persian poet, is difficult to say with confidence. Apparently it seems to be Mir's own invention.

One possibility is that Mir might have made ḳhvush-aḳhtar a metaphor for the beloved, and he might have assumed the cause of similitude to be that the beloved has abundant beauty, and a person who has so much beauty will be called 'fortunate' (the way an unattractive person or a deformed person is called 'unfortunate'; that is, if someone is unattractive or deformed then he is unfortunate, and if he is attractive or sound in body then he is fortunate).

The phrase kis ḥusn se kahūñ maiñ is also enjoyable-- 'what ornament of elegant style might/would I adopt?'. Or, 'there is no such beautiful ornament'. Or again, 'beauty' can mean 'beautiful one'-- 'before which beautiful one might/would I describe the ḳhvush-aḳhtarī of the beloved?'. To fill a commonplace kind of theme with so much meaning was an addiction that only Mir was able to pursue.

FWP:

SETS == A,B
MOTIFS
NAMES
TERMS == FRESH WORD; METAPHOR; WARRANT

Here's a real 'A,B' verse, in which the relationship between the two lines can be construed in an enjoyable variety of ways.

The first line offers a version of the 'kya effect'; it can be read as asking with what beauty/charm the speaker could describe her beauty (a question); or as indignantly denying that he could find words of sufficient beauty/charm for her beauty; or even as boasting of what beauty/charm he could put into describing her beauty.

The second line builds on these possibilities, in one of several possible ways:

=The second line simply describes her beauty (this is the reading that SRF uses).

=The second line explains why the speaker cannot properly describe her beauty (her beauty is so potent that it undoes him, as it would undo even Jupiter).

=The second line represents his (successful?) attempt to offer a description of her beauty that is itself full of 'beauty/charm'.

The various possibilities of tāb (see the definition above) also work perfectly in the second line, and help to give it some claim to providing 'beauty/charm' of description. Her beauty is so radiant that she outshines Jupiter; or, her beauty is so powerful that Jupiter is unable to overcome it; or, her beauty is so overwhelming that Jupiter cannot at all endure it.

Also, as SRF notes, the unusual expression ḳhvush-aḳhtarī deserves 'fresh word' credit.

Note for grammar fans: The kī at the end of the first line of course modifies a colloquially-omitted bāt .