In Mixed letter coding type of questions, three or four complete messages are given in the coded language and the code for a particular word is asked. To analyse such codes, any two messages bearing a common word are picked up. The common code word will mean that word. Proceeding smilarly by picking up all possible combinations of two, the entire message can be analysed.
If 'ish lto inm' stands for 'neat and tidy' ; 'qpr inm sen' stands for 'small but neat' and 'hsm sen rso' stands for 'good but erratic', what would 'but' stand for ?
In the second and third statements, the common code word is 'sen' and the common word is 'but'.
So, 'sen' means 'but'.