External Grep Process

array=('hello' 'world' 'my' 'name' 'is' 'perseus')
word="world"
if echo "${array[@]}" | fgrep --word-regexp "$word"; then
    : # do something
fi

Bash Regular Expression Test

array=('hello' 'world' 'my' 'name' 'is' 'perseus')
word="world"
if [[ "${array[@]}" =~ " $word " ]]; then
    : # do something
fi

There will always technically be iteration, but it can be relegated to the shell's underlying array code. Shell expansions offer an abstraction that hide the implementation details, and avoid the necessity for an explicit loop within the shell script.

Handling word boundaries for this use case is easier with fgrep, which has a built-in facility for handling whole-word fixed strings. The regular expression match is harder to get right, but the example below works with the provided corpus.

External Grep Process

array=('hello' 'world' 'my' 'name' 'is' 'perseus')
word="world"
if echo "${array[@]}" | fgrep --word-regexp "$word"; then
    : # do something
fi

Bash Regular Expression Test

array=('hello' 'world' 'my' 'name' 'is' 'perseus')
word="world"
if [[ "${array[*]}" =~ (^|[^[:alpha:]])$word([^[:alpha:]]|$) ]]; then
    : # do something
fi