Qaza’ means shaving part of the head and leaving part of it.
Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him) said in al-Sharh al-Mumti’ (1/167): Qaza’ means shaving part of the head and leaving part of it. It is of different types:
1-
Where the shaving is not done properly, so some hair is shaved on the right side and on the left, and on the front, and on the back [i.e., separate parts of the head are shaved and the rest is left].
2-
Where the middle is shaved and the sides are left.
3-
Where the sides are shaved and the middle is left.
4-
Where the front part only is shaved and the rest is left.
End quote.
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The one who cuts his hair on the sides of his head more than the middle comes under the heading of qaza’, which is forbidden. Al-Bukhaari (5921) and Muslim (2120) narrated from Ibn ‘Umar that the Messenger of Allaah (blessings and peace of Allaah be upon him) forbade qaza’. Naafi’ (one of the narrators of the hadeeth) said, explaining qaza’: Shaving part of a boy’s head and leaving part.
Al-Nasaa’i (5048) and Abu Dawood (4195) narrated from Ibn ‘Umar that the Prophet (blessings and peace of Allaah be upon him) saw a boy part of whose head had been shaved and part of it left. He told them not to do that and said: “Shave all of it or leave all of it.” Al-Albaani classed it as saheeh in Saheeh al-Nasaa’i.
That includes cutting some of the hair short and leaving some.
It says in Fataawa al-Lajnah al-Daa’imah (5/175):
What is the ruling on leaving some of the hair longer than the rest?
Answer: Abu Dawood narrated from ‘Abd-Allaah ibn ‘Umar (may Allaah be pleased with him) that the Messenger of Allaah (blessings and peace of Allaah be upon him) forbade qaza’ and said: “Shave all of it or leave all of it.”
it says in Sharh al-Iqnaa’: Qaza’ includes shaving some places on the sides of the head, or shaving the middle and leaving the sides, as most of the Christians do, or shaving the sides and leaving the middle, as many of the foolish do, or shaving the front and leaving the back. Ahmad was asked about shaving the back of the head and he said: This is the action of the Magians, and whoever imitates a people is one of them. Thus it is known that it is not permissible to leave some parts of the hair longer than others.
‘Abd-Allaah ibn Ghadyaan, ‘Abd al-Razzaaq ‘Afeefi, Ibraaheem ibn Muhammad Aal al-Shaykh. End quote.