| pulsation(noun, oscillation, regularity of recurrence periodicity) |
| reciprocation(exchange, switch, interchange, transaction, trading) |
| reciprocity(noun, connection, association, exchange, parallel) |
| wavering(noun, anxiety, weakness, uncertainty, shake) |
| alteration(noun, change, fluctuation, permutation) |
| battledore and shuttlecock(expression, idiom) |
| chain(noun, set, run, group, conclusion) |
| cycle(noun, set, run, sequence, series) |
| irresolution(noun, anxiety, weakness, uncertainty, shake) |
| measure for measure(expression, idiom) |
| mutability(noun, change, anxiety, weakness, sport) |
| period(set, round, sequence, series, rhythm) |
| permutation(change, fluctuation, interchange) |
| quid pro quo(expression, idiom) |
| regular wave motion(expression, idiom) |
| sequel(noun, set, run, course, conclusion) |
| sequence(noun, set, run, group, course) |
| series(noun, order, set, run, group) |
| shift away |
| something for something(expression, idiom) |