Constipation, which is a functional problem, makes it hard for you to have a bowel movement (or pass stools), the stools are infrequent (less than three times a week), or incomplete. Constipation is often related to inadequate “roughage” or fiber in your diet, or a disruption of your regular routine or diet.

Constipation causes you to strain during a bowel movement. It may cause small, hard stools and sometimes anal problems such as fissures or hemorrhoids. Constipation is rarely the sign that you have a more serious medical condition.

https://my.clevelandclinic.org/health/articles/7040-gastrointestinal-diseases