The phrase "picked up on" refers to the recognition or noticing of a particular detail or cue. Synonyms for this phrase include "caught on to," "sensed," "perceived," "detected," "grasped," "understood," and "comprehended." Each of these words conveys a similar meaning and can be used interchangeably with "picked up on" depending on context. Additionally, other possible synonyms for "picked up on" include "noticed," "observed," "discerned," "identified," and "spotted." By understanding these synonyms, you can add variety to your vocabulary and communicate your ideas more effectively.