AN 4.140
Four persons: one able to convey the intent but not the letter; one able to convey the letter but not the intent; one able to do neither and one able to do both.
Read the Sutta
Recommended translation: Professors, Olds translation
Index to available translations: AN 4.140
Four Types of Professors Found in This World
The Professor who is baffled by the sense
not the letter.
The Professor who is baffled by the letter,
not the sense.
The Professor who is baffled by both the sense
and the letter.
The Professor who is baffled by neither the sense
nor the letter.
It is, however, impossible, there is no probability,
that the Professor, who is possessed of the four analytical powers (having knowledge of sense; knowledge of things; knowledge of etymology; and having his wits about him),
could be baffled by both the sense and the letter."
— p.p.
The Buddha concludes this sutta with the statement that one who has the four paṭi-sambhidā could not falter in both the conveyance of the intent and the conveyance of the letter.
Paṭi-sambhidā paṭi: (reflect back on) + sam = co, con, with; + bhida break apart, analyze.
That which is reflected back upon analysis ... in this case of the intent, the form, the roots, and the manner of rhetorical exposition of a teaching.
Woodward: the Four Analytical Powers;
Bhk. Bodhi: The Four Analytical Knowledges
These are:
1. attha, the spirit or intent of word, phrase or complete exposition;
2. dhamma, one authority (U. Pandi, pg. 377 Points of Controversy) says this is understanding the word, another (the Abhidhamma) understanding the logic behind an expression —
it is possible to merge these two sets of ideas
'this is said this way (the word) because people hear this expression thus (the reason)',
'this is said in this order (the word) because in this way it has such and such an effect on the mind (the reason)'
'this is said this way (the word) because this is the order in which the idea expresses its evolution and logical basis (the reason); etc.
but this may be a confusion of this term with the next, and the meaning of 'dhamma' is 'thing', 'form' or 'the Word' and the Abhidhamma always tries to make things appear more obscure than they are and in this case they are trying to make this into knowledge of Dhamma. But that would make this not a universal set of tools of analysis, but one directed at this Dhamma only and usually when Gotama is speaking about his Dhamma he makes it clear that that is what he is doing;
3. nirutti, the knowledge and intuitive knowledge of the roots of both word and phrase and the proper grammatical construction thereof (for example, etymology, or understanding the origin and meaning of an idiomatic expression).
In what I have called 'Old Pāḷi' where the letter is a syllable, a syllable is a word, and a word is a sentence, the explanation of the word in the science of Nirutti is more along the lines of the explanation of the origins and meaning of the idiomatic expression than the construction of a 'word' from the meaning of its 'syllables'. A Pāḷi 'word' is something like a Chinese pictogram. And like such, a Pāḷi word can be read forwards and backwards and assumes different meanings with different inflections (rather than being a separate word with 'different' spelling, long ā, etc.) and is to be understood in multiple ways — that is, not in many separate ways but in many ways simultaneously. The same thing happens in English even today, but the phenomena goes mostly unnoticed ... except in certain cases of madness 
What we have in the dictionaries is a selection from the possibilities, not the entire scope.
Not understanding this is the source of many misunderstandings made by modern linguistic analysis. It is a form of linguistic imprisonment constraining us to one reality. ... and it is always breaking down.
4. paṭibhāna (see Discussion of AN 4.132), the knowledge of (and inspired access to) rhetorical expression, enrapturing turn of phrase, tactics in the conveyance of an idea. Ahum.
