台Taivo A Taiwan Mandarin dictionary

有色無膽

yǒusèwúdǎn

ㄧㄡˇ ㄙㄜˋ ㄨˊ ㄉㄢˇ

Simplified 有色无胆

1to be perverse and suggestive towards the opposite sex, but shrinking back when provoked to act on it
2to have perverted thoughts but no guts to actually do it
3to be all talk and no action

Keep 有色無膽 and it comes back until you know it.