sullen: Merriam-Webster: used to describe an angry or unhappy person who does not want to talk, smile, etc.
Smile mask syndrome (Japanese: スマイル仮面症候群, Hepburn: sumairu kamen shōkōgun), abbreviated SMS, is a psychological disorder proposed by professor Makoto Natsume of Osaka Shoin Women's University, in which subjects develop depression and physical illness as a result of prolonged, unnatural smiling.
Some people just aren't prone to smiling—they may be shy and unsure of themselves, self-conscious about their appearance, or simply don't feel the need to offer smiles to all and sundry. They may have been raised in families or cultures where smiling wasn't as frequent as it is in others.
The antonym of 'smile' is 'frown' or 'glower'. An antonym is a word that has the opposite meaning of another. 'Frown' and 'glower' function as verbs just like 'smile'.
Perhaps you could use smirk, although that carries the connotation of smugness. Or, perhaps simper, which is a shy smile.
A note to single dudes: If you're looking to pick up a woman at a bar, whatever you do -- don't smile at her. Women are actually less sexually attracted to smiley, happy men, suggests a new University of British Columbia study, published online today in the journal Emotion.
Some people just aren't prone to smiling—they may be shy and unsure of themselves, self-conscious about their appearance, or simply don't feel the need to offer smiles to all and sundry. They may have been raised in families or cultures where smiling wasn't as frequent as it is in others.
The rarest smile type is the complex smile, with only an estimated 2% of the population possessing this smile. This smile is rare because it requires three muscle groups to work simultaneously when smiling.
The dampened smile is an attempt to control an automatic, happy one and exists because some muscles, such as the ones controlling the mouth, are easier to suppress than others.
Smiling depression could be a deliberate attempt by the depressed person to hide their true feelings, but it can also be unintentional. Sometimes, people with smiling depression don't know why they keep smiling, and they may not trust their own feelings. They may not even recognize that they are depressed.
Some People Prefer Not to Smile
Personal Preferences – Some people simply aren't prone to smiling. They may be shy, have problems with confidence, or not feel the need to smile. It may also be that they were raised in a family or culture where smiles weren't readily offered.
Harry Styles crowned winner of 'world's most attractive and impressive smile' - Mirror Online.
Julia Roberts
There is no doubt about the fact that this gorgeous woman, 57, is the Queen of Hollywood Smiles.
Children with Moebius syndrome often have trouble moving their faces. For example, they may not be able to smile, frown, raise their eyebrows or close their eyelids.
Friendly, trustworthy, and agreeable
When you flash a genuine smile, it's an open invitation saying you're friendly and willing to interact with others. You're also perceived as more trustworthy and agreeable. A true smile shows you're willing to cooperate and that you're worthy of another person's time and attention.
That's because we typically want to express warmth and connection. So when you stand up to speak and you smile at your audience, they will probably smile back. This will initiate a subconscious and powerful connection.
People who smile less broadly risk appearing 'contemptuous' if they show their teeth, US researchers found. Instead, if your grin is smaller and less effusive, a tight-lipped smile may make you look more genuine and friendly.
This gives your smile an unhealthy appearance, which others will notice. According to a study done by the ADA, smiles are the most attractive physical feature on a person, as many people find smiles more appealing than eyes, hair, or body shape.
Smiling increases socially perceived attractiveness and is considered a signal of trustworthiness and intelligence.
Bashful means shy or timid.
A complex smile lives up to its name. It's the most complex smile style, and it's also the most rare, found in only about 2% of people naturally. A complex smile combines the movements in both the other smile styles and adds to it a simultaneous lowering of the lower lip.
introvert. mouse. recluse [⇒ thesaurus] shybie (informal) wallflower.
Your Body Releases Good Hormones
Your body releases three hormones that make you feel good when you smile. They include dopamine, endorphins and serotonin. These signal to your body that you're happy, and in turn, you feel happier.