I just go through what written by Sir Rudiger, Amazing. Sir explained very well.
being a Urdu tutor and as I know, the correct word is " فلک شگاف " "Falak shagaf" (there is no "L" in "Shagaf").
so what is this meaning, "Falak" is "Sky" and "Shafaf / شگاف " is " Crack / hole" but I think it is more better if you say "Crack". therefore "Falak Shagaf" = Sky Crack

but, it's mean that the one who have power to "reach the sky" or have great vision which crack the sky, or have great power that he can look inside the sky.

one another meaning is "Very loudly" means very loudly sound. let me give you a very common example we use in routine life. 

" فلک شگاگ نعروں میں آواز سنائی نہیں دے رہی تھی" this is very common sentence.

ساکت و صامت / saakat-o-saamat

ساکت و صامت

This is the entry of the online Persian dictionary http://www.vajehyab.com/dehkhoda/

It is most probably a Persian expression used in Urdu. Please note that in classical Urdu it should be pronounced "sākit-o-sāmit." It can mean something in the line of "completely silent" / "silent and unmoving"

حلق / halq

This means "throat", and could also mean "windpipe" or even "oesophagus."

John T. PLatts, A Dictionary of Urdū, Classical Hindī, And English

فالک شگلف / falak shagalaf

There is no فالک, so this is probably a typo for فلک It can mean "heaven" "sky" or "fate"

Thank you for Your help, Rüdiger! I really appreciate it.

Sorry, that was a typo. From extensive Research I discovered that فلک شگاف  means terrifying/dreadful!