This is the 'system negative' value. The 4 is the opposite of the 8 valuation.
The basic rules for use of 4 are similar to those for the use of 8. When used purely as an adjective then the 4 follows any other number, as in 64 which means 'a bad result'.
When the negative aspect is what is focused upon more directly the 4 comes first, as in 49, which means 'slow'.
 
The reasons why something is unsatisfactory are not specified but could be followed up in more detail with ordinary language.
 

• 74 this is bad
• 714 this is a mess
• 64 a poor result; disappointing
• 24 a poor way to do things; ineffective
• 34 an ineffective person
• 54 what is wrong?
• 49 slow
• 47 error
• 42 bad way forward; a problem
• 48 danger
• 41 poor input; high cost
• The different positioning of the 4 is shown in the following usage:
• 34 a person who is ineffective
• 43 a bad person

 
In the first case the emphasis is on the 'person' who happens to be ineffective; in the second case the emphasis is on 'badness' which happens to be carried by a person.