Practical detailed study gets boy qualified (10)
I believe the answer is:
reasonable
'practical' is the definition.
(thesaurus)
'detailed study gets boy qualified' is the wordplay.
'detailed' means to remove the last letter (the word must be end-less or 'de-tailed').
'study' becomes 'read' (synonyms).
'gets boy' becomes 'son' (I am not sure about this - if you are sure you should believe this answer much more).
'qualified' becomes 'able' (I've seen this before).
'read' with its final letter taken off is 'rea'.
'rea'+'son'+'able'='REASONABLE'
Can you help me to learn more?
(Other definitions for reasonable that I've seen before include "description of rationality" , "Not excessive or extreme" , "Sound" , "Fair - inexpensive" , "Fair, rational" .)