Without signal around lake that's very small (9)
I believe the answer is:
minuscule
'very small' is the definition.
(minuscule means extremely small)
'without signal around lake' is the wordplay.
'without' becomes 'minus' (minus means without).
'signal' becomes 'cue' (as in an actor's cue).
'around' is an insertion indicator.
'lake' becomes 'L' (geographical abbreviation).
'cue' placed around 'l' is 'cule'.
'minus'+'cule'='MINUSCULE'
'that's' is the link.
(Other definitions for minuscule that I've seen before include "not capital" , "unimportant" , "Fine" , "A lower-case letter" , "Not important" .)