1.
at most, at best
Indicating the upper limit of what can be expected; no more than.
精々100人ぐらいだろう。
It's probably 100 people at most.
私にできるのは精々これくらいだ。
This is about all I can do.
今の給料では、精々月に一回外食できるくらいだ。
With my current salary, I can eat out at most about once a month.
2.
as much as possible, to the best of one's ability
Doing something with maximum effort (often with slight resignation or irony).
精々頑張ってください。
Do your best (as much as you can).
Can sound slightly dismissive depending on context
時間があるなら、精々楽しんでこい。
If you have time, enjoy yourself as much as you can.
残り少ない休みなんだから、精々ゆっくり休んでおいたほうがいい。
You don't have much vacation left, so you'd better rest as much as you can while you have the chance.
精々 indicates a maximum limit or doing one's best.
NUANCE:
- When indicating limits: "at most," "at best"
- When encouraging: can sound slightly ironic or dismissive, like "well, good luck with that"
COMMON PATTERNS:
- 精々〜くらい/ぐらい (at most about ~)
- 精々頑張る (to do one's best)
NOTE:
Unlike 少なくとも (at least), 精々 sets an upper limit.
Related Words
Contrast:
少なくとも (at least)