#Definition of a Sahih Hadith :
In the technical convention of the sciences of hadith,
a sahih hadith is the one
1.whose chains are connected (Muttasil)
2.which has the just (i.e impartial) narrators,( Adalat)
3.which has the narrations from those that have a firm grip over their memorization,(tammuzzabat)
4.There should not be any oddity: [No SHAZZ] :
A trustworthy narrator (siqah) should not be contradicting another most trustworthy narrator (ausaq).
5.No hidden defect in the hadith: There shouldn’t be any hidden defect in the narration (which is not obvious) .
(NO Illat khafiyya kadihah)
Some scholars have considered the addition of [tammuzzabat] absolutely necessary so that the difference between sahih and hasan is understood. Hadith with [tammuzzabt] is considered sahih and the one with [khafeefuzzabat] is considered hasan.
Linguistically : dhaeef (weak) is the opposite of quaviy (strong). The weakness can be physical or abstract meaning :
Technically : a weak hadith is a hadith in which the criteria of a hasan hadith are not completely found.
It’s the kind of weak hadith in which baseless things are attributed to the Prophet ﷺ.