How to find all entries containing a word as a whole word only?

I am using Toad for Oracle and I have a Table called CO_EXCEPT_TEXT_LG.
The Table is similar to the below:

I'm trying to pull all entries that have the word 'UNLOCK' as a whole word only. (In this case, this would be entries 1, 3 and 4.)

I have tried the following so far:

1. WHERE ACTION = 'UNLOCK': gives Entry 3
2. WHERE ACTION LIKE 'UNLOCK': gives Entry 3

(I think LIKE without wildcards essentially functions like '='. Correct me if I'm wrong!)

3. WHERE ACTION LIKE '%UNLOCK%': gives Entries 1,2,3,4

4. WHERE ACTION LIKE 'UNLOCK%': gives Entries 1,2,3

Assuming that the word boundaries you want are spaces, here is one way to do it with like:

where ' ' || action || ' ' like '% UNLOCK %'

We could also use a regex:

where regexp_like (action, '(^|\s)UNLOCK(\s|$)')

... where ^|\s means: either the beginning of the string (^) or a space (\s) - while $ represents the end of the string.