«مع فصاحة كلماته»
Provided that its individual words are also eloquent.
This condition prevents an otherwise fluent, grammatically acceptable, and intelligible sentence from being considered eloquent if it includes a defective word. In «شعره مستشزر», the phonetic heaviness belongs to the single word “mustashzir.”
Contrast: «قرب قبر حرب» is difficult because of words placed together; “mustashzir” is difficult as a word in its own right. Their diagnostic locations differ.