thumb noun
VERB + THUMB suck | flick, jab, jerk ‘What'll we do with them?’ he asked, jerking his thumb at the suitca | raise, stick out He smiled and raised a thumb in greeting. I stuck out a thumb and a car stopped immediately. | twiddle (often figurative) I sat there twiddling my thumbs until the manager finally appeared.
THUMB + NOUN nail (also thumbnail)
PHRASES between finger and thumb/between thumb and forefinger I picked up the beetle carefully between finger and thumb. | thumbs up He made a thumbs-up sign through the window to tell us everything was fine.
You can also check other dicts: thumb (English, 中文解释 ), wordnet sense, Collins Definition