Beliefs are those mental statements, or thought patterns, about ourselves, others and this world that we perceive are true.

Beliefs help us make sense of and function in this world. They can be about very practical or  philosophical matters.

And, majority of our beliefs through our earliest cognitive development stages (during the first few years of our life).

The psyche seems to be indeed built in such a way that, from birth till about the start of adolescence, we absorb beliefs from people perceived as figures of authority, often without even questioning them.

And, as we grow older these beliefs sink deeper into our consciousness to shape our reality and influence our thoughts.

Also, beliefs are also absorbed at a young age from cultural influences and religion, and therefore from society in general. 

A belief is limiting when it prevents us from  being  or  doing  what  our  soul or more importantly what our spirit within it truly desire. As such, it should be changed.

As limiting beliefs are much associated with the mental energies and lower Chakra energy. Without clearing these repressed energy, it is often difficult to change or improve on those limiting beliefs.

Limiting beliefs are usually found on QiMen chart with 6-Yi harm (六仪击刑) or in BaZi chart that have punishment formation (i.e. 丑未戌,寅巳申,辰午酉亥,子卯) in the year and month pillars. And if this punishment formation extend to day and hour pillars, it would represent that these limiting beliefs extend into marriage and retirement.

Hence, when you see this in a QiMen or BaZi chart, it likely the Querent had with him/her limiting beliefs.