Nearly plunge doctor into salt solution (6)
I believe the answer is:
almost
'nearly' is the definition.
(synonyms)
'plunge doctor into salt solution' is the wordplay.
I cannot quite understand how this works, but
'doctor' could be 'mo' (medical officer) and 'mo' is present in the answer.
an anagram of 'salt' is 'alst' which is present in the left over letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for almost that I've seen before include "As good as" , "Not entirely" , "Slightly short of" , "Nearly, not quite" , "Not totally" .)