Peering in closer, I found a little line in print (5)
I believe the answer is:
serif
'line in print' is the definition.
(stroke attached to a letter in some typefaces)
'peering in closer i found a little' is the wordplay.
'peering in' indicates a hidden word.
'SERIF' can be found hidden inside 'closer i found little'.
(Other definitions for serif that I've seen before include "Short line at the end of the main strokes of a printed character" , "Style of type-face" , "Stroke's foot" , "Letter feature" , "Feature of some typefaces" .)