If the letter after still nun or tanwin is not one of the six throat letters, not one of the six assimilation letters, and not ba, it falls among the remaining fifteen letters and requires ikhfa haqiqi, or true concealment. The fifteen are ت، ث، ج، د، ذ، ز، س، ش، ص، ض، ط، ظ، ف، ق، ك.
The nun is neither pronounced as an entirely distinct clear n nor completely assimilated into the following letter. Instead, its tongue articulation is not completed as a full clear n, while nasal resonance is retained before articulating the next consonant.
Examples: «أَنْذَرْتَهُمْ» takes concealment before dhal, and «مِنْ قَبْلِ» before qaf. In neither phrase is the nun released as a completely separate clear consonant.