In "Doctrinal Discussion" Randy Bland writes:
One definition of pride is an inordinate opinion of one’s own dignity, importance, merit, or superiority. This definition is an apt description of the Pharisee in Jesus’ parable. Humility, on the other hand, is defined as having a modest opinion of one’s own importance. Perhaps we should add that it is having a true opinion of one’s own importance. The publican knew exactly who he was and where he stood before God. Such knowledge is the most important thing when it comes to living lives of humility.
Discussion: What kind of opinion do we possess?
Source: Jesus, Son of God: Adult Teacher's Insights, page 50.