Dot three i's perhaps. Many find it silly (7)
I believe the answer is:
idiotic
'silly' is the definition.
(I've seen this before)
'dot three i's perhaps many find it' is the wordplay.
I cannot really see how this works, but
'many' could be 'd' and 'd' is found in the answer.
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is found in the answer.
'i' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for idiotic that I've seen before include "Silly" , "Stupid, foolish" , "Inviting ridicule" , "Mindless" , "Witless" .)