Unmistakable
Definition 1 of 2
Pro Tip 1/3
No Doubt Here
Use 'unmistakable' when you are 100% sure and there is no room for doubt. His joy was unmistakable when he received the acceptance letter.
Pro Tip 2/3
Not Interchangeable
Don't use 'unmistakable' if something could be confused with another thing. The red markings on the bird are unmistakable, unlike the common varieties.
Pro Tip 3/3
Sensory Clarity
'Unmistakable' is often used to describe a clear sense, like smell or sound, that can't be confused. The unmistakable sound of rain on the roof comforted the travelers.