What is the difference between probable in indication and explicit in indication?

The difference between a text with probable indication and one with clear indication lies in the clarity of its meaning:

Probable Indication (Dhanī al-Dalālah): This refers to a text whose words can carry more than one meaning. Examples include the verse: {وَالْمُطَلَّقَاتُ يَتَرَبَّصْنَ بِأَنْفُسِهِنَّ ثَلاثَةَ قُرُوءٍ} (And divorced women shall wait for three periods), where "al-qurūʾ" has been interpreted as either purity (ṭuhr) or menstruation (ḥayḍ). Another example is the verse: {فَتَيَمَّمُوا صَعِيداً طَيِّباً} (then perform tayammum (definition) with pure earth), where "al-ṣaʿīd al-ṭayyib" has been interpreted as either pure (ṭāhir) or that which produces vegetation (munbit).

Clear Indication (Qaṭʿī al-Dalālah): This refers to a text that clearly points to a specific meaning and does not admit any other interpretations. Examples include the verse: {لِلذَّكَرِ مِثْلُ حَظِّ الْأُنْثَيَيْنِ} (for the male, what is equal to the share of two females), and the verse: {حُرِّمَتْ عَلَيْكُمْ أُمَّهَاتُكُمْ وَبَنَاتُكُمْ} (Prohibited to you are your mothers and your daughters).

The texts of revelation are divided into these two categories. Some Sunnah (definition) texts have clear indications, such as the Prophet's (peace be upon him) saying: "On buried treasure (rikāz) is one-fifth." Others have probable indications, such as his saying: "There is no prayer for one who does not recite the Fātiḥah of the Book," where the negation might refer to sufficiency (ijzāʾ) or perfection (kamāl).