The word "al-Taqiyya”literally means: "Concealing or disguising one’s beliefs, convictions, ideas, feelings, opinions, and/or strategies at a time of eminent danger, whether now or later in time, to save oneself from physical and/or mental injury.”A one-word translation would be "Dissimulation."
Non-muslims allege that Muslims practice this in order so that they can trick non-muslims, so they put their guard down so Muslims can offensively attack them. This is untrue. Islam promotes openness and honest at all times, except where your life or safety is directly threatened, then at that time you can conceal your islamic beliefs or strategies. Every religion and people believe in this. Say you are a Christian soldier in the crusades, and you are captured by an enemy. Are you now supposed to tell the truth and give up the whereabouts of your camp, and have your army decimated? No, that wouldn't make sense. Further, if you are asked by a genocidal group seeking to kill all Christians if you are Christian, is lying and saying no, a sin? Of course its not.
And as we see Taqiyya is simply common sense.
Sunni Muslims when confronted with this criticism by non-muslims, say, "Well that's a Shia thing". This is simply not true. Shias preach this rule more often, simply because Shias were persecuted more often by the majority sunni government. However, in fact, Sunni's do believe in Taqiyya, they just are not educated in their own religion to know this.
Example 1: From the Quran:
Jalal al-Din al-Suyuti in his book, "al-Durr al-Manthoor Fi al-Tafsir al- Ma’athoor,”narrates Ibn Abbas’, the most renowned and trusted narrator of tradition in the sight of the Sunnis, opinion regarding al-Taqiyya in the Qur’anic verse: "Let not the believers take for friends or helpers unbelievers rather than believers: if any do that, (they) shall have no relation left with Allah except by way of precaution ("tat-taqooh"), that ye may guard yourselves ("tooqatan") from them....(3:28)”that Ibn Abbas said:
"al-Taqiyya is with the tongue only; he who has been coerced into saying that which angers Allah (SWT), and his heart is comfortable (i.e., his TRUE faith has not been shaken.), then (saying that which he has been coerced to say) will not harm him (at all); (because) al- Taqiyya is with the tongue only, (not the heart)."
Note: The two words "tat-taqooh”and "tooqatan,”as mentioned in the Arabic Qur’an, are BOTH from the same root of "al-Taqiyya.”
Note Also: The "heart”as referred to above and in later occurrences refers to the center of faith in an individual’s existence. It is mentioned many times in the Qur’an.
Example 2: Sunni Source:
Ibn Abbas also commented on the above verse, as narrated in Sunan al- Bayhaqi and Mustadrak al-Hakim, by saying:
"al-Taqiyya is the uttering of the tongue, while the heart is comfortable with faith."
Note: The meaning is that the tongue is permitted to utter anything in a time of need, as long as the heart is not affected; and one is still comfortable with faith.
Source and further reading: https://www.al-islam.org/shiite-encyclopedia-ahlul-bayt-dilp-team/al-taqiyya-dissimulation-part-1
