It's stupid to begin in an easy job (5)
I believe the answer is:
inane
'it's stupid' is the definition.
(I've seen this before)
'begin in an easy job' is the wordplay.
'begin' indicates taking the first letters.
'easy' indicates anagramming the letters (a loosened or easy version of the letters).
'job' becomes 'ne' (I can't explain this - if you can you should believe this answer much more).
The first letter of 'in' is 'i'.
'an' anagrammed gives 'na'.
'i'+'na'+'ne'='INANE'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for inane that I've seen before include "Lacking sense, silly" , "Foolish, fatuous" , "Fatuous, mindless" , "Moronic" , "Frivolous" .)