A spontaneous or unposed photograph.
"The photographer managed to capture a candid shot of the child laughing without realizing the camera was out."
"The photographer asked for a candid shot to capture his true reaction without posing."
characterized by directness in manner or speech; without subtlety or evasion
"blunt talking and straight shooting"
"a blunt New England farmer"
"I gave them my candid opinion"
"forthright criticism"
"a forthright approach to the problem"
"tell me what you think--and you may just as well be frank"
"it is possible to be outspoken without being rude"
"plainspoken and to the point"
"a point-blank accusation"
informal or natural; especially caught off guard or unprepared
"a candid photograph"
"a candid interview"
openly straightforward and direct without reserve or secretiveness
"his candid eyes"
"an open and trusting nature"
"a heart-to-heart talk"
Impartial and free from prejudice.
"The judge made a candid assessment of the evidence, ruling without bias toward either party."
In plain English: Candid means being honest and open about your true feelings without hiding anything.
"She gave me some very candid advice about my career path."
The word came into English from the Latin candidus, which originally meant white. Over time, its meaning shifted to describe something honest or straightforward because a person dressed in pure white robes was seen as unblemished and trustworthy during Roman elections.