legs together
Legs held together along their entire length, with no or minimal separation between them.
The legs may or may not be crossed, and it doesn't matter if the character are lying, sitting, or standing. A thigh gap may be present depending on the character's proportions. Contrast with legs apart and spread legs.
If a character's legs are touching at the knees but their feet aren't touching, use knees together feet apart instead.
If a character's knees and toes are touching, but their calves and heels are apart, do not use legs_together. Pigeon-toed is likely the proper tag.
If a character's legs aren't entirely visible but appear to be together, use your best judgment when determining whether to use this tag. A good example of legs touching is Danbooru post #2620773.