捉摸不定

unpredictable; elusive; hard to pin down

to clutch / to grab / to capture

to fathom / to make sense of / to grasp

to feel with the hand / to touch / to stroke / to grope / to steal / to abstract

variant of 摹[mo2]

no; not so / (bound form) not; un-

indefinite / indeterminate / (botany) adventitious

to set / to fix / to determine / to decide / to order