To hide your feelings/intensions from others

Hide

- We hid our anger under a big smile.

- She tried to hide her excitement after wining the contest.

- You should not hide your grief and sorrow after your father's death.

Conceal

To hide your intentions or feelings from someone:

- John concealed his sorrow from me.

- He could not conceal his surprise .

- She has never concealed her ambition to be the Miss of the world

Disguise

To hide opinions, ,feelings or intentions etc by pretending to feel something else:

- He didn't disguise his bitterness about what had happened.

- A thinly disguised attempt to embarrass the prime minister.

- She couldn’t disguise the fact that she felt uncomfortable.

- disguised his anger behind a false geniality.

Camouflage

Hide or disguise a feeling,an intention,etc by means of camouflage.

- He believed that her kindness was merely a camouflage for her real intentions.

- The constant party going of her later years was a desperate camouflage for her grief.

- Aggression is often a camouflage for insecurity.

- Her angry words were camouflage for the way she felt.

Mask

To deliberately avoid showing your feelings in your behavior or the truth about a situation, so that it cannot be easily seen or noticed:

- Dena lit a cigarette, trying to mask her agitation.

- Men often mask their true feelings with humor.

- She spoke calmly, masking her anger.

- She masked her anger with a smile.

- He masked his real purpose.

- She made a desperate attempt to mask her horror at the news of her father's death.

dissemble

A word often used in literary style meaning To disguise or conceal your real feelings,intentions often by pretending to have different ones:

- She smiled, dissembling her true emotion.

- She had, as far as he knew, no reason to be curious, and therefore no reason to dissemble her curiosity.

dissimulate

A formal word meaning To disguise (one's intentions, for example) under a feigned appearance or by lying:

- We don't need to dissimulate our lack of interest to gain the power.

- She smiled to dissimulate her anger.

Suppress

To stop yourself from showing an emotion, especially one that might offend someone:

- Anya sucks at the insides of her own cheeks to suppress a smile

- she could not suppress a rising panic.

- She was unable to suppress her anger.

- He could hardly suppress his surprise.

- As Karen nodded, Rory failed to suppress a shiver.

Repress

To not allow something, especially feelings, to be expressed:

- Denying or repressing sorrow often seems the easiest way out when confronted with death.

- We should not suppress or repress our anger feelings.

- I couldn't repress a sigh of admiration.

- He was unable to repress his laugh.

- You mean --; Cheltenham?'; said Robert, unable to repress a smile.

- For much of the day we need to be able to repress some feelings to enable us to concentrate or to use our intellects.

- Such people give more than they take; they tend to hide their emotions and repress their desires just to please others.

Bottle something up

To deliberately avoid showing strong feelings or emotions especially if you are angry,worried or upset.

- Patients who bottle up their feelings are often helped by being encouraged to express these emotions.

- He was a great believer in expressing aggression, not bottling it up.

- I've been bottling it up inside me far too long.

- Nearly six months after the tragedy, he's still bottling it up.

Be non- committal

To avoid showing what you think about something or what you intend to do,when answering a question or making a statement:

- The manager remained non committal about the chances of his team to win the match.

- The president was non committal about his plans to bring the economy out of the recession.

- She was non committal about her decision to get divorced .

Put on a brave face/put a brave face on /put on a good face

To pretend that you are happy about a situation while you are upset.In American English you can also say put on a good face.

- He was putting a brave face on it but she knew he was shattered.

- He failed in his exams but he tried to put a brave face on it.