This is the 2591st most frequent Russian word.
страх
Fear.
Here, 'страх' is used as a noun to represent an abstract feeling of fear.
У него был страх перед выступлением.
He had a fear of performing.
In this case, 'страх' is a possessive noun to specify the type of fear, heights.
Она преодолела свой страх высоты.
She overcame her fear of heights.
Here, 'страх' is the subject of the sentence, indicating the force obstructing the action.