Lacking a cryptic clue for "tiny" (9)
I believe the answer is:
minuscule
'tiny' is the definition.
(I've seen this in another clue)
'lacking a cryptic clue' is the wordplay.
'lacking' becomes 'minus' (I've seen this before).
'a cryptic' indicates anagramming the letters (a cryptic or obscure order of the letters).
'clue' is an anagram of 'cule'.
'minus'+'cule'='MINUSCULE'
'for' is the link.
(Other definitions for minuscule that I've seen before include "not capital" , "Fine" , "A lower-case letter" , "Not important" , "unimportant" .)