Gasp oddly, seeing holes (4)
I believe the answer is:
gaps
'holes' is the definition.
(I've seen this in another clue)
'gasp oddly' is the wordplay.
'oddly' indicates an anagram (letters in an odd order).
'gasp' is an anagram of 'GAPS'.
'seeing' acts as a link.
(Other definitions for gaps that I've seen before include "Breaks, spaces" , "Breaks or openings as in hedge or fence" .)