المعنى الاصطلاحي :

Adopting a hard-line approach in worship and exceeding the proper limits with regards to the religious commands and prohibitions.

الشرح المختصر :

"Ta‘seer" (make difficult) is to make things hard and adhere to difficulty in worship, thus overburdening oneself or others in the matters of religion by going beyond what is prescribed, or in worldly matters by abandoning what is easier – unless it is a sin. "Ta‘seer" contravenes the leniency and tolerance of Islam. Indeed, the most pleasing among all religions to Allah is the true tolerant religion of Islam. Therefore, the Prophet, may Allah's peace and blessings be upon him, commanded the Muslims to adhere to "tayseer" (facilitate matters), to shun "ta‘seer", and to avoid placing unnecessary burdens and difficulties upon themselves or others.

التعريف اللغوي المختصر :

"Ta‘seer": derived from "‘usr", which means difficulty and hardship; opposite. Opposite: "tayseer" (facilitating), "takhfeef" (lightening).