Supports us with cheers during lapses (8)
I believe the answer is:
sustains
'supports' is the definition.
('sustain' can be a synonym of 'support')
'us with cheers during lapses' is the wordplay.
'with' says to put letters next to each other.
'cheers' becomes 'ta' (both can mean thank you).
'during' indicates putting letters inside.
'lapses' becomes 'sins' (I've seen this in another clue).
'us'+'ta'='usta'
'usta' going into 'sins' is 'SUSTAINS'.
(Other definitions for sustains that I've seen before include "Supports, keeps alive" , "Supports physically or mentally" , "Bears" , "keeps going" , "Nourishes or bolsters" .)