And I have filled him with the spirit of God, in wisdom, and in understanding, and in knowledge, and in all manner of workmanship
Wisdom (Strong's #2451)
The verbal root for this word is חכם (hhakham) and means to separate between good and bad, right and wrong, left and right, up and down, etc. This is often used in the context of a skilled workman as in Exodus 28:3, "And thou shalt speak unto all that are wise (hhakham) hearted, whom I have filled with the spirit of wisdom, that they may make Aaron's garments to consecrate him, that he may minister unto me in the priest's office." These workmen are filled with the spirit of "wisdom" which is in the Hebrew חכמה (hhakhmah), the noun form of the verb חכם (hhakham). A person with wisdom is one who has the ability to separate between good and bad, right and wrong, left and right, up and down, etc.
Understanding (Strong's #8394)
The Hebrew word for understanding is תבון (tavun) comes from the verbal root בין (biyn) meaning to "understand" but the more deeper meaning of this word can be found in a related verbal root - בנה (banah) which means to "build." In order to build or construct something one must have the ability to plan and understand the processes needed. This is the idea behind the verb בין (biyn) and its derivative noun תבון (tavun), to be able to discern the processes of construction.
Knowledge (Strong's #1847)
The Hebrew word for knowledge is דעת (da'at), a noun derived from the verb ידעodi (yada) meaning "to know." The idea of "knowing" in Ancient Hebrew thought is similar to our understanding of knowing but is more personal and intimate. We may say that we "know" someone but simply mean we "know" of his or her existence but, in Hebrew thought one can only "know" someone if they have a personal and intimate relationship. In Genesis 18:19 God says about Abraham "I know him" meaning he has a very close relationship with Abraham. In Genesis 4:1 it says that Adam "knew Eve his wife" implying a very intimate sexual relationship. Knowledge is the intimate ability to perform a specific task or function.
With the more in-depth meaning behind these three words we can better understand Exodus 31:3 as follows;
And I have filled him with the spirit of God, with the ability to distinguish between the good and the bad, and with the ability to discern the processes of construction, and with an intimate ability to perform the tasks, and in all manner of workmanship