Finding exact match in vim

Question

Using / or ? enables to find a match for a word in vim. But how can I find an exact match? For example, my text contains the following words: a a

Answer 1

To find a single, standalone aa (not a, aaa, ...), you need to assert no match of that character both before and afterwards. This is done with negative lookbehind (\@ in Vim's regular expression syntax) and lookahead (\@!) enclosing the match itself (a\{2}):

/\%(a\)\@

Simplification

Those assertions are hard to type, if the border around the match is also a non-keyword / keyword border, you can use the shorter \<\a\{2}\> assertions (as in MosteM's answer), but this doesn't work in the general case, e.g. with xaax.