The former mayor who boldly demanded due process in his resignation speech was more subdued Tuesday as he pleaded guilty to three criminal charges.

A thinner, morose Bob Filner shifted and stood with his hands clasped together as he admitted to one count of felony false imprisonment and two counts of misdemeanor battery.

In exchange for pleading guilty, Filner avoids prison time and the spectacle that would come with a trial.

But what exactly did he admit on Tuesday?

False imprisonment

What it is: A person commits false imprisonment when he holds another person against his will. The offense is considered a felony when force is used.

Even briefly inhibiting another person can be considered false imprisonment, said attorney Kerry Armstrong, who has worked on numerous false imprisonment cases.

The alleged offense: At a March 6 fundraiser, Filner restrained an unidentified woman and used force to overcome her resistance.

Examples: Simply locking a door so another person can’t escape could be considered false imprisonment but Filner admitted to something more serious.

Armstrong gave two examples of felony offenses.

One was the so-called “PB groper,” who was accused of a series of incidents in which he grabbed women who were walking or jogging in Pacific Beach. In another instance, a young woman alleged a man she had just met clutched her hand and forced her to touch his genitals.

In both cases, forcibly holding the woman constituted felony false imprisonment.

Battery

What it is: Battery is simply unwanted touching.

The alleged offenses: An unidentified woman went to City Hall on April 6 to meet with Filner during his monthly office hours. When she got her turn to meet with Filner, he kissed her on the lips without her consent.

On May 25, another woman attended a rally and clean-up event on Fiesta Island. When she saw Filner, she asked if they could take a picture together. Before the photo was taken, Filner groped the woman’s rear end.

Examples: A punch or a slap is enough to constitute misdemeanor battery.

Touching another person’s genitals or even kissing him or her without consent could be considered sexual battery.

Armstrong said prosecutors could have sought sexual battery charges based on what’s been made public in the Filner case.