لو

لَا (a. neg. partic. It is generally placed before the Aorist), No.
b. Not.

لَا أَعْلَمُ
a. I do not know.

لَا تَفْعَلْ ذٰلِكَ
a. Do not do that.

الغِنَى بالَمَعْرِفِة لَا
بالمَالِ
a. Wealth consists in knowledge, not in riches.
لَا خَيْرَ فِى الحَرْب
a. There is no good in war.

وَلَا
a. Not yet; not even; nor.

لَا بُدّ
a. There is no escape, necessarily.

لَا جَرَْمَ
a. Assuredly, undoubtedly.

لِئَلَّا
a. see under
لَيَلَ

لِئَن
a. Because, in so much as.

لِأَي
a. For what? Why?